The Armored Core series of games usually have hidden parts for your Humongous Mecha in some stages along with getting graded for beating the stage. There's also a combat arena in most games which also net you parts. Some games even count your mission complete/fail ratio. So getting 100% can take some time, and true 100% means you can't screw up once. Getting 100% usually gets you more parts. But the Armored Core series has a lot of Mission Pack Sequel games between next installments, so it means something in the end. Armored Core for Answer takes the cake: getting 100% nets you an emblem. Then again it's Nineballs emblem — the game series memeticThat One Boss. Also, in-universe, some of the characters have 100% mission success rates, but that doesn't mean anything.
Blast Corps is incredibly persistent. Clear the main levels, find all the scientists, save a shuttle, clean up the moon, find all the bonus levels, get gold on all the bonus levels, find everything on the main levels, get gold on all the secret planet levels, get gold on all the time trials for the main levels, and your reward for all this is unlocking platinum targets for all the levels. The reward for getting all platinums is a very appropriate rank.
Batman Arkham Asylum has things such as the various puzzles and challenges that the Riddler has scattered throughout Arkham for Batman to find. Listening to him gradually succumb to his inferiority complex as you find more and more of them is really quite fun.
Batman Arkham City is even more infuriating than Arkham Asylum when it comes to 100% completion - assuming they have the 4 DLC packs, the player needs to complete the main storyline and all side missions twice, complete all 440 Riddler story mode challanges (riddles, trophies, etc.) and aquire all 888 Riddler's Revenge medals.note There are 31 maps with 3 medals each at a total of 93; these then need to be played again in packs of 3 (maps 1+2+3, then 4+5+6, etc.) for a further 129 medals. These 222 medals then need to be acquired again as Catwoman, Robin, and Nightwing. As a reward, you finally get to punch The Riddler in the face.
In Bayonetta, the achievements/trophies are actually a part of the game in the form of "Umbran tears of blood". Getting the 51 achievements and catching the 51 crows hidden throughout the game (both required to beat the hardest difficulty setting) will give you the Climax Bracelet, a Game Breaker item. And if you are really hardcore, you can collect 10 million halos to fight a Nintendo HardBonus Boss − for which the aformentioned Climax Bracelet will actually be useful − who will reward you with a secret weapon. Which you can use in the Bonus Level Of Hell Angel Slayer, to unlock a new character named Little King Zero. And if you still don't have enough, try and get platinum awards in every chapter on Normal to unlock Jeanne as a playable character. Pfiou!
The fifth ending of Drakengard requires that you collect every weapon in the game first, which is completely arbitrary, as what weapon you have equipped doesn't even matter to the plot of this ending. And the ending itself is rather anticlimactic.
NieR (which takes place in the future of the fifth ending) uses the same formula for getting all the endings, but the weapons are infinitely easier to get. Unlike Drakengard, however, the endings are more climactic and all Tearjerkers.
The God Of War games kinda have this in terms of unlockables. Each one is locked in the main menu and it tells you exactly what you need to do to unlock it. This varies from completing that game's challenge mode to completing the Harder Than Hard difficulty. Good luck with that.
Ghost of Sparta has most of its unlockables purchasable using blood orbs, and purchasing them all lets you play as freaking Zeus... but only in the combat arena.
A similar example is Jet Force Gemini for the N64; the player was also required to collect all the "Tribals" in the game to reach the final boss.
Katamari Damacy takes this to the point of insanity: beating the game once opens a bonus level in which you are asked to collect one million roses, no more than 10 at a time. (Thankfully, you aren't required to do this all in one sitting.) Completing this task unlocks some slight graphical tweaks (roses everywhere) and a new song.
In most Katamari games, there's a catalog of all the items you can roll up, with a brief description of it by the King of All Cosmos. It doesn't contribute to overall game completion and is totally optional, but many completionists strive to fill it in, which can be a very daunting task.
Getting 100% completion on your save file in Kid Icarus: Uprising involves completing the story, obtaining at least one level of every Power, opening every Intensity Gate, and collecting all the Idols. That last one is interesting, because there are some Idols that can only be gotten by scanning AR Cards, and while they aren't necessary when it comes to collecting them all, they still give percentage completion points. So by obtaining them, it's possible to go over 100%. There are also several achievement lists in the game, but those don't count towards 100% completion. Instead, they have their own completion percentage, and you'll pretty much need to do everything that's needed to get 100% game completion in order to get 100% achievement completion, making that the true sign that you've conquered everything in the game (especially as that's the only percentage that's shown off to the players you Streetpass with).
In LEGO Star Wars (1), collecting all of the minikit pieces from a chapter got you a single piece of a larger ship. Getting all Minikits and True Jedi Status for every chapter unlocked the Episode 4 preview.
The amount of "collectibles" has been greatly increased for LEGO Star Wars II as compared to Lego Star Wars (1), with red power bricks.
In the DS versions, though, it's made tougher by the fact that in vehicle levels, in order to get a minikit piece, you must not die.
This is made easier when you find the 'Invulnerable' red brick. Then you can't die no matter what you do.
The PC version of LEGO Rock Raiders features a cinematic of the LMS Explorer getting its engines charged up and heading home, one that plays when the player gets a score of 100% on every level. But because one level doesn't contain enough energy crystals to meet its crystal requirement, it's impossible to see the movie without digging through Program Files.
Billy Mitchell became the most famous gamer on the planet for being the first to complete a "perfect game" of Pac-Man. This consisted of not only clearing every level that could be completed (255), but eating every fruit and ghost in every single level.
Getting all 50 Oboro coins in the PS2 version of Shinobi will unlock the final piece of artwork in the Concept Art Gallery, as well as an extra stage in Trial Mode that is nothing more than a glorified training stage.
Near the beginning of Spider-Man 2: The Movie, snarky narrator Bruce Campbell tells you that if you activate all of the 200+ Hint Markers (icons that provide hints spread throughout the city), he will say something different every time you activate them again. Several hours later, after activating the last marker, you activate it again, expecting more snarky advice. And Bruce says..."something different". Yes, the phrase "something different".
The third game has a similar issue. Photographing all the bad guys, beating gangs, collecting spider tokens to unlock a black suit you no longer have any goddamn need for because the tokens only appeared when you took down Venom for the last time...perhaps the worst is the meteorite fragments, which unlock you a large yellow "CONGRATULATIONS" sign.
Super Bomberman 5 keeps a percentage on your save file, which represents how many of the game's 100 levels you have cleared. Good luck doing this without a guide; not only do you have to be skilled at Bomberman, but you must also figure out the paths to levels you haven't reached yet. The game's highly non-linear. Each stage can have up to five different exits, and boss stages look identical save for the fact that they'll take you to different starting points in the next world.
After you acheive 100% Completion, you can go for 200%. It's easier this time around since high-quality powerups will appear more often.
The Yakuza series has a massive amount of mini games, side quests, and hidden items. It's possible to complete the main story and still have over 90% of the game to complete.
Viewtiful Joe unlocks a new mode or character each time you complete the game on normal or harder with certain requirements. Unlocking Sylvia and V-Rated mode are fairly easy, but Super V-Rated, Alastor, and Captain Blue to play are a bit harder - the toughest of which requires beating V-Rated or Super V-Rated with Rainbow V ranks in every single mission.
Viewtiful Joe 2 also has the harder difficulties unlocked by beating the game, but instead of new characters has the 36 Chambers unlocked when certain achievements are performed. True completion means unlocking everything and beating all 36 Chambers with a Rainbow V rating.
The Binding of Isaac has a golden god achievement which is gotten after getting all the items in the game during playthroughs.
Graffiti Kingdom's story portion is relatively easy to get through, but obtaining all the attacks and monster cards can be insanely tough at times. (How were you supposed to figure out that defeating a certain number of frogs on that bridge would cause the only monster in the game with Poison Breath to appear?) The only thing you get for obtaining everything is the ability to create anything you want and see all the enemy models in detail.
In Harry Potter and the Chamber of Secrets, if you find all the Chocolate Frog cards (there are about 40), you will be able to open a bonus area. Doing so requires collecting Chocolate Frog cards hidden in challenge/test areas for each of your classes, which must be completed within time limits (although you can replay them) as well as thoroughly searching the castle and grounds.
Collecting all the masks in The Legend of Zelda: Majora's Mask resulted in you receiving the Fierce Deity's Mask at the end of the game. It is easily the most powerful mask in the entire game, but is only usable during boss fights. Each earned mask also corresponds to a piece of the Segmented Ending, showing the happy ending of whomever you helped in order to earn the mask.
The Legend of Zelda: Skyward Sword has, along with the main quest, 80 gratitude crystals, all sorts of mini-games (one of which gets the Hylian Shield), many Goddess Cubes, and plenty of upgrades, bugs, and treasures.
To get 100% in The Legend of Zelda: The Wind Waker, you have to collect a figurine of every single character in the entire game. To get a figurine, you have to take a photograph of the character, then go to a particular island and have somebody make the figurine from your photo. Your camera can only hold 3 photographs at once. There are three hundred characters in the game, and more than a dozen of these can only be photographed at specific times: if you miss your chance, you miss your shot at 100%, though you can take a New Game Plus for a second chance after you beat the game. Also there are a few characters that only appear when you make use of a Game Boy Advance linked to your Gamecube making 100% completion impossible if you do not own a GBA and a Link Cable. This nets you yet another trophy (Link on board of The King of Red Lions), which is unobtainable otherwise.
In Maximo, there is a secret level named "Mastery" that requires you to get 100% completion to enter.
In Okami, collecting all 100 Stray Beads nets you a Game Breaker for your New Game Plus. Completists will also want to acquire at least one of every type of fish and treasure as well as feed 100% of all animals. On the topic of that last one, there is one dog that can be Lost Forever, though it's not out of the way. When you go to the past Kamiki Village, feed the dog in the village.
Several of the Tomb Raider games have secrets (via items or just hidden rooms) which usually contain extra health and ammo. While some of the games' secrets are nothing but bragging rights when you get 100%, the 3rd game unlocks a bonus level for you to explore and beating that gets you all guns with infinite ammo for any level you play over.
The Uncharted games play with this, dotting treasures around the world for you to find. 100% completion requires 61/60 treasures in the first game and 101/100 in the following two. The rewards are things like weapon select, character skins, making of videos and the like.
The adventure games Indiana Jones and the Last Crusade and Indiana Jones and the Fate of Atlantis had "Indy Quotient" as score. In fact, it was two separate scores: one for what you had gained during the current playthrough, and another one which kept track of all score-giving actions you have accomplished in the game on any play. To gain full score in the latter includes doing things which are nearly impossible or result in an instant death, such as punching Hitler in public.
The third The Legend Of Kyrandia game parodied the scorekeeping mechanic of other contemporary adventure games. The stated maximum score is 911, but the developers have admitted that they pulled the number out of thin air, and it is absolutely impossible to actually reach that score. Points are often awarded for completely irrevelant and nonsensical actions, such as tripping over a log.
Sierra adventure games like Space Quest have a points score of "X out of X" at the top of the screen. Some of the puzzles have multiple solutions, with the most difficult solutions required to reach a perfect score. This becomes even more complicated because Sierra is the master of the Last Lousy Point.
The Baten Kaitos games love to torture completionists. Eternal Wings had about 1,000 magnus that have to be collected for 100% completion. As if that wasn't daunting enough, there are a lot that can easily be Lost Forever; the Trail of Souls is the most infamous offender, but Maskless Mizuti is another nasty one.
Origins, meanwhile, has the torturous Pac-Man sidequest, which involves feeding Pac-Man 147 different quest magnus. In addition, there's also the 'Milly's Rocks' sidequest, which involves pushing humanoid rocks around Nekkar. Thankfully, the game eased up on the Lost Forever; only three quest magnus and four field guide entries are missable.
The Achievements for Blue Dragon require you to, among other things, find every single item, every single monster, and max out every single character and character class. It's only for fun though, and the game's pretty much over after you beat the final boss (not counting New Game Plus).
Dragon Age: Origins has the "Easily Sidetracked" achievement for completing 75% of all side-quests (no ordinary feat, considering it's a BioWare game) and the "Traveler" achievement for visiting every location in the game. The stage of the Final Battle counts as one.
A gamer finished up Dragon Quest IX with a 100% completion rate. Amount of hours played? 773 HOURS.
Final Fantasy VII had the Master materia; collect and master one of every kind of materia of a particular type, and you would be rewarded with a single materia that gives you all of the capabilities of all the rest of them combined, giving you more options in combat than you could possibly have otherwise. The optional bosses might count, though they generally don't give you any items that you couldn't get somewhere else.
Rewards for completing side quests are becoming more popular in Final Fantasy; Crisis Core: Final Fantasy VII featured 300 extra missions that needed to be done for full completion of the game, not to mention many a Guide Dang It side quest. The reward is a literally God-level Zack, though. New entry to the series Dissidia: Final Fantasy features an achievement system with some very obvious goals such as completing each character's story line and number of battles fought, along with some obscure ones such as distance traveled across the game's maps and how high you can raise your luck level, to make 150 "missions" in all.
With Final Fantasy IX's Tetra Master, getting perfection in the form of a perfect Collector's Rank of 1700 is insane. To do this, you have to collect all 100 card types (and you can only have 100 cards total at a time). On top of that, you have to "level up" your cards by using them enough so that they all have an attack type of A, and have a different pattern of attack arrows on each one. Your reward for doing this, however, is very disappointing. "Would you like to discard?" is superimposed over the other text in the card menu. Yes, that's right, for all your hard work, you get a glitch.
Final Fantasy X-2 is the only game in the series that scores players based on how much of the game they've completed, and it's notoriously sadistic about it—miss a single obscure, time-sensitive quest, pick the wrong option in an arbitrary choice, neglect to sleep at the Trauma Inn at least once a chapter even though it serves no gameplay purpose, or even skip a cutscene, and you lose any hope of 100% completion. Fortunately, your completion percentage will carry over to a New Game Plus.
There are two paths through the main plot, depending on which faction you ally with early in the game. If you take the other path in a New Game Plus, you can earn the additional completion points that weren't available on the first path, making it easy to reach ~130% completion (the game stops tracking at 100%). On the other hand, if memory serves, the two paths have slightly different numbers of points, so it's only possible to reach 100% completion in a single playthrough if you pick the right path - and then only by beating the Secret Dungeon - 100 floors of increasingly difficult fights - by about floor 90, the random encounters are with boss monsters - not only that, but the best equipment in the game only appears once, so without going through a new game plus several times, your party will be underequipped too. Getting 100% completion without a New Game Plus may be possible, but it's far, far, far easier (and quicker!) to just play through the New Game Plus
The Xbox 360 version of Final Fantasy XI has achievements for getting jobs to level 75. Since there are 16 jobs in the game, and getting one to level 75 takes at least a month of dedicated playing, getting 100% achievements will take a very, very long time.
Getting the highest clan rank in Final Fantasy XII requires you not only to kill every mark, but also to complete the Sky Pirate's Den, the game's proto-achievement list. Among the achievements are things like encountering every monster in the game (including all the rare monsters), triggering every Quickening finisher at least once and having visited every section of every game area (thankfully excepting the ones you can't return to.)
Final Fantasy XIII, being on the PS3 and 360, supports Trophies/Achievements, which provides a percentage figure to work towards. To get all of the trophies, you will have to (among other things) earn a five-star rating on all 64 Marks, and acquire every weapon and accessory in the game (not all at the same time, but you have to have had at least one of every unique item at some point). Given the game's Upgrade system, this means not only acquiring all of the basic weapons and accessories, but also leveling them up.
Final Fantasy XIII-2 has 160 Fragments to collect, which nets an achievement. It also unlocks the cruelest Secret Ending in history, featuring the villain mocking the player for trying to find a way to defeat him.
In the original Kingdom Hearts, you had to lock all the worlds, rescue all the Dalmatians, and beat the Hades Cup to get an extra bonus movie after the credits. A later release of the game required you to do all the Trinities and beat Kurt Ziza as well, but gave you a longer movie.
In Kingdom Hearts II to get the final movie you must do several things. Unlock all the worlds. You have to completing Jiminy's Journal, which includes collecting all synthesis items, which are often quite rare monster drops and take a long time to find. And then you need to find enough to synthesize all the items too. You also need to level all your drives and summons up to Level 7 (very difficult with Final Form, as it requires defeating 500 nobodies in total while transformed), and then beat the Hades Paradox Cup with 15,000 points. However, on Proud mode you just have to unlock the worlds.
Maxing out all your social links in Persona 3 Portable or FES gives you the colorless mask. With that, once you reach level 99, you can fuse Orpheus Telos, a Palette Swap of your first persona, but one that is strong against every attack in the game (except Almighty attacks), and can inherit any move in the game. With a lot of work, time, and intensive planning, you can create persona with the eight best moves in the game, which would normally require 8 different persona. Of course, maxing all the social links requires an absolutely perfect understanding of the games relationship sim mechanics, and fighting normal gamer instincts to move the plot forward for as long as possible, as you just don't have the time to succeed otherwise. Or in other words: a guide. He is also necessary to get 100% of the persona compendium, meaning you've had every persona at least once, although achieving that gives you absolutely nothing. Completing all of Elizabeth's side quests gets you nothing, but completing certain ones are necessary to get all the items and persona in the game.
Unlike Persona 3, maxing your social links in one playthrough in Persona 4 doesn't give you access to the ultimate persona. You have to get the true ending for that. And maxing all of your social links in one playthrough only gives you a trophy in the Updated Rerelease but if you want 100%, you'd still be wanting to do it anyways, which like the above example, pretty much requires a guide. It is also best saved for your New Game Plus playthrough as you need your social stats to be maxed to get access to the best answers to some links. Of course you'll need to max them all anyways to get 100% in the persona compendium anyways but in this case they don't all have to be maxed in one playthrough.
Completing the Pokédex just awards you with a star on your Trainer card. If you really want to get technical, 100% completion would involve the player getting all 5 possible stars on their cards. This includes challenges such as winning a Master Rank Super Contest (DPPt), stealing 50 flags from friends in an underground minigame and winning 100 battles in a row at the Battle Tower (just so you know, after around 50 the game begins fielding teams full of legendaries and cheating like no tomorrow).
Pokemon Crystal Enhanced is one of many rom hacks that allows the player to get all avaliable Pokemon in the one copy of the game.
Radiata Stories has the interesting quality of having at least 120 characters that can join your party, all of which must be added to your Friends List through various means. It's impossible to get all the characters on one go, as the story branches halfway through the game and some characters are only found on one path or the other. When you do get every single character, you get an extra little picture on your Friends List. Hooray?
To achieve 100% in Riviera: The Promised Land, you have to view all of the CG scenes, collect all of the items, use all of those items' Overdrive Moves, and defeat the Bonus Boss after completing the game. And to get all CG scenes, you have to finish the game SIX times!
Star Ocean Till The End Of Time features "battle trophies"; as you unlock more, you get things like more difficulty levels and extra characters for the pseudo-fighting game Mini-Game. The challenges include things like beating bosses within a particular amount of time, or at low levels, getting X number of combos, walking X number of game-feet, playing for X amount of time, etc. One of the trophies is for defeating the last Bonus Boss in under two hours on the highest difficulty setting. This is actually quite difficult to accomplish.
Star Ocean The Last Hope also has Battle Trophies. This time around, however, they are character specific; each of the 9 playable characters have 100 trophies to obtain, for a total of 900 Battle Trophies.
In all of the Suikoden games, you get the true ending only if you have all 108 Stars of Destiny in your party.
Except III, in which all you get is the ability to play through the game as the antagonist, though part of the "Where Are They Now?" Epilogue changes.
Like most Tales games, Tales Of Symphonia has an item completion book which records all the items that come into your inventory. It takes two whole playthroughs and going through another 85% of the game before you complete the listing. And that was only if you were very careful in manipulating relationships between characters.
In addition, there's also the "Monster Book", which records every monster you encounter. Since there is one point where depending on which choice you made at an earlier time the boss is different it will take at least 2 playthroughs to record every enemy. The one good thing is that, contrary to popular belief, you don't need to record all the stats (which requires you to have a certain character use a certain item on each enemy). Your reward? A title for one character.
The more recent Tales Of The Abyss has something similar. The reward for completing the item list? A title for a single character that comes with a small stat boost and access to a special store.
Most Wild ARMs games will offer special Ex. Game rewards for completing particular challenges, such as opening every chest in the game, filling in every spot on the world map, getting to Level 100 with all characters, or beating particular bosses.
The World Ends With You has 22 secret reports, 96 Noise reports, 472 items, and 304 pins to collect (and a SpeedrunBoss Rush which only counts on tougher difficulties). Completing each set gets you a star rank for that collection and a new character on the save screen. Collecting all the secret reports also unlocks The Stinger. Then there's your ESP'er score... You gain one point for each battle cleared and each item bought worth more than 10,000 yen. And you need exactly 10,000 points in the US version to achieve God rank. One more and you're back down to Demon.
Melee has nearly 300 trophies (290, plus three special ones), special items that you receive by fulfilling certain conditions in-game. Each trophy is modelled after a character, item, or setting from a Nintendo game, and comes with a little bit of trivia regarding the item it represents.
Call of Duty: Modern Warfare 2 played this straight, displaying the completion percentage in each of its mode: Singleplayer, Spec-Ops, and Multiplayer.
Interestingly, after entering Prestige Mode in the multiplayer, the counter will go up past 100. A player level 25 in 3rd Prestige, for example, may have their percent counter at 454%. The ULTIMATE completion (that is, 10th Prestige) will display 1100%.
DOOM had several goals to shoot for per level: a time target, monsters killed, and secrets found. On Nightmare difficulty, however, monsters would respawn, making it possible to get more than 100% monsters killed, and at least one 'DOOM construction kit' actually advocates creating a 'secret area' that the player can't reach, to keep them coming back to look for 'that last 10 percent'.
This is actually carried forward — minus the respawns — from id's previous game, Wolfenstein 3D, although there is more incentive to get 100% completion for each category (kills, secrets and treasure collected) because you are awarded bonus points for doing so.
To get the best ending in Painkiller, you not only have to beat the game on Nightmare difficulty, you also have to beat the card condition on each level and unlock their respective cards...which unlocks Trauma difficulty, beating which finally rewards you with the best ending.
In both Castlevania Chronicles Of Sorrow games, Aria of Sorrow and Dawn of Sorrow, Soma not only has 100% map completion to look forward to, but 100% soul collection as well. Every non-human enemy in the game, save for their respective final bosses, has a soul that will randomly drop when Soma kills it, giving him a new power to play around with. Obtaining the soul of every enemy in the game will give him access to the infinite-MP Chaos Ring. Needless to say, this is extraordinarily difficult, with some souls refusing to drop until you slaughter the enemy 100 times or more.
Castlevania: Portrait of Ruin takes this to an even greater extreme, with percentage markings for map completion separate for each map, as well as a combined total (1000.00%). In addition, there are percentages for items found/obtained, enemies fought (which are written in gray letters unless the player battles the enemies enough times to obtain the items they drop), and subweapons/skills obtained.
Castlevania Symphony Of The Night allows you to explore 100% of the map. This score can then be increased to 200.6% in a "mirror" version of the castle; if you exploit a couple of wall bugs, you can increase this to ~240%!
Most every item in Symphony of the Night is a random drop from enemies. Though these items don't count toward a noted in-game percentage, completionists who want to collect them all will be tortured by the low appearance rates, which result in revisiting the same room upward of one hundred times to get a single item. Further, certain items such as the Muramasa Blade and Familiars can be even be "leveled up," and the maximum level is only achievable by killing literally hundreds of thousands of enemies. Extreme collectors can gather 99 of every item in the game if they don't have anything else to do for the next few years.
K.O.L.M.: There are a bunch of metal plates to collect, each with a letter on it. If you have them all at the end of the game, they spell out It's Kind Of Like Metroid
A series-long example: Each game in the Metroid series since Super Metroid has a percentage. While earlier games in the series, including Super Metroid itself, gave different endings based on completion time rather than percent, percent has now become a factor in determining which ending you get, actually displacing time in the Prime sub-series for technical reasons. Zero Mission actually features two prizes for getting 15% or lower! note One for 15% in Normal mode, and one for 15% in Hard mode. 9 items are required to complete the game, and it's generally recommended you fill five of the remaining slots on Super Missiles and Energy Tanks, with the last slot going to either Screw Attack or Speed Booster. Either way, you'll need to have mastered the game and Bomb Jumps.
This factor actually varies from version to version (if you're playing the game on Hard). The European version can be completed on both Normal and Hard with 9% but the Japanese and US versions require a 10% completion rating on Hard due to a quirk at the end of the game concerning destructible blocks.
Players of Metroid Prime Trilogy can get a whopping 300% completion, or 100% per game.
To reach the final battle with Specter in the Ape Escape series, the player is required to obtain 100% completion (by capturing all the monkeys). However, monkeys aren't the only collectible in Ape Escape. You can reach the final battle without any Specter Coins, for example.
Not to mention the gold medal you have to get for every level's time trial.
In Banjo-Kazooie, collecting 100 Jiggies will extend the ending, where Mumbo shows you three secrets and talks about Banjo-Tooie.
In Banjo-Tooie, collecting 90 Jiggies unlocks the Character Parade in Replay Mode.
Banjo-Kazooie: Nuts & Bolts gives you an achievement and a gamerpic if you get all the Jiggies.
Several Crash Bandicoot games have taken it all the way up to 120% and above, starting with Crash Bandicoot 3: Warped which offered 105% completion for clearing the two hidden levels, collecting all the bonuses on them, getting at least a golden relic on every single level's time trial, and finally collecting the hidden gem in the main warp room.
Crash Bash features up to 200%, but good luck getting there.
De Blob is a HUGE PAIN to get 100%; not only is there a time limit, but each level takes more than 15 minutes to complete and when you finish it, the level saves your scores and resets, meaning if you go back to it it's completely unfinished and you have to do EVERYTHING over again.
Donkey Kong King of Swing took it even higher with 200%. To get it, you must collect all 24 medals and 20 Crystal Coconuts, collect all the medals again in Diddy Mode, beat all the top times as both Donkey Kong and Diddy Kong in Time Attack Mode, and place first on all of the Jungle Jam events (including three that are only unlocked through a password screen accessible only through a code).
Donkey Kong Country Returns also has 200% as its maximum amount. However, the only things that count towards completion percentage are the Kong letters (since you need them all to open all the stages) and completing said stages and then completing them again in Mirror Mode. Puzzle pieces and Time Attack medals don't factor in.
It takes hours of searching to 100% complete Kirby: The Amazing Mirror, even with the Master power.
Kirby's Epic Yarn tracks completion in several categories, from characters encountered to fabric textures acquired and so on. The "Flicks" category is the only one you're guaranteed to complete simply by finishing the main plot. And for each category you finish... a bell appears that strikes a unique note. Woo-hoo?
In Mega Man Powered Up, if you chose to play through the game in New Style, you can play through 13 stages in all. Not too bad, right? Then there are the Difficulty Levels, which are 3 in all. And it's available in all the stages, totaling up to 39 possible stages. Not daunting enough? Now factor in every Secret Character in the game: Cut Man, Guts Man, Ice Man, Bomb Man, Fire Man, Elec Man, Time Man, Oil Man, Mega, Roll, and Proto Man. That's twelve characters in all (Mega Man, Mega Man S, and Mega Man C are all considered the same character, as is Roll and her various costumes). Combined with the aforementioned stages and difficulty levels, you'd end up with 468 stages to complete to achieve 100%! Old Style? No difficulties, no additional characters, all you have to do to get 100% here is to clear all 10 stages. That's it.
Mega Man X takes this approach literally, giving you a percentage number that corresponds with how many challenges you have completed. The normal game is relatively short, and will take 5 or 6 hours to complete, less for Mega Man veterans. But the challenges will take many more hours to complete. Essentially, the game doubles or triples in length if you go for 100% Completion. Getting a 100% requires you to beat all challenges with a Gold Medal, which requires you to beat each challenge without taking any damage, among other things. Your only reward for doing this is showing an S Rank on the challenge screen.
In Psychonauts, not only can you clear all the figments, emotional baggage, and cobwebs from every in-brain world, and collect the items from the scavenger hunt, but it's also fun to try to talk to, punch, burn, telekenetically lift, and read the minds of every single character you come across.
The level total actually goes up to 101, because of one bonus level given for clearing a combat mini-game. Doing this on the Steam version gets an achievement titled Math is Hard.
For 100% Ratchet & Clank you simply had to beat the game with all thirty skill points. Some of these skill points were simple things, such as going through a level without taking damage, others required blind luck, and worse still, some are Guide Dang It conundrums. However, one of the skill points was to buy all the weapons and gold weapons, which were only available on the second playthrough, and required all the gold bolts you'd been collecting for the full set. Though these were unlocked on the first level, assuming you had the money, which chances are you didn't if you saved up for the RYNO.
Ratchet And Clank Going Commando complicated things somewhat. Full completion was still tied to the skill points, but the skill points now included things like getting all the crystals in the Tundra Wastes, upgrading all the weapons (twice, once in the regular game, once in New Game Plus), finding all the hidden health upgrades and maxing your health out. However, due to the way the skill points were set, and the fact that the platinum bolts were merely used for weapon mods, it was possible to get all the skill points, without doing all the Mini Games or finding all the hidden items.
In Ratchet & Clank: Up Your Arsenal however fixed all this. Full completion was tied to a set of statues, one for every possible thing in the game, such as arena challenges, maxing out the weapons, maxing out health, beating all the ranger battles, and getting all the skill points, which now included things such as complete speedruns of all the bonus sections in the game.
The first Rayman game requires 100% completion (breaking all the Electoon cages) to get to the final level.
Scaler has two endings, the good ending with both the main character and his dad returning from the alternate world, and a bad ending where his dad doesn't make it back. Completing the game with anything less than 100% gives you the bad ending.
In Sly 3, 100% earns you "a music video". It's actually totally worth it. Watching it on YouTube doesn't do it justice.
Getting every emblem in Sonic Adventure 2 Battle unlocks a 3D version of Green Hill Zone. Unfortunately, that means completing every mission with an A rank (some of which are nigh impossible, such as getting 100 rings in a set amount of time when there are only 114 rings in the level), surviving three boss rushes, one racing mini game, and beating all the races and all the levels of karate with your chao.
This has unfortunately become standard in most if not all Sonic games since, sometimes with little to no reward.
There's also getting Amy in Sonic Advance 2 which means you have to get all the Chaos Emeralds 4 times, which is really tough to do. She's also a clone of Sonic on top of that and to 100% the game you have to all Chaos Emeralds a 5th time with her.
Lastly, there's filling the Treasury and getting all Followers and 5-Stars on every mission in Sonic and the Black Knight which requires playing all the Missions multiple times and most are really hard and even more annoying.
Each game in the original Spyro trilogy brought different rewards for 100% completion: The Big Bad's treasure vault in the first game, an unlimited supercharged flame breath in the second, and a final level with tons of treasure and the last dragon egg in the third.
The third one had what is possibly one of the most satisfying of all 100% completion rewards. After you collect every gem and every dragon egg, you meet Moneybags, the irritating bear that you had to pay so many precious gems to get him to do things like lower a bridge or start a fan. He offers to sell you access to the final level for the cost of every single gem you've collected. What follows is the player chasing him around, ramming into him horns-first until he coughs up every last gem he took from you.
Thoush this is the false 100% reward. The real one, gotten by doing this and getting absolutely everything but the Skill Points, is a new world filled with minigames and gems. And a rematch with the Sorceress for the final Egg.
Season of Ice took this to the extreme: you had to have 100% to finish the game.
Also from Spyro: Skill Points. They are like Achievements before Achievements. Getting all of them in Spyro 2 gave you the "Epilogue" and some concept art for things that didn't make it.
In Super Mario World, there are seventy-one levels (not counting Bowser's castle) with ninety-six possible exits between them. Your game file is updated to reflect not the percentage of the game or number of levels you've cleared, but the number of exits you've found. When you get ninety-six, a little star appears in your save file. In addition, for completing the Special World, you are treated to a Halloween-themed palette shift in the world map, and in the levels themselves, the Koopas wear giant Mario masks instead of shells, the piranha plants become jack o'lanterns, and the Bullet Bills become pidgits. (Other ports vary this change in some way, but the general idea is intact.)
In Super Mario World 2: Yoshi's Island, getting 100% on every level in a world opens up both an additional level and a bonus game which can be played an infinite number of times for extra lives and/or inventory items. Achieving 100% completion, however, requires collecting twenty red coins, thirty star points, and five flowers, which is insanely tougher than it sounds, because it's not the type of game where you can miss one and go back in and get it later. You have to pick everything up in one go.
One of the GBA exclusive levels, World 5-Secret ("Items are fun!"), actually seems to assume that everyone is going for 100 percent completion. The goal ring is in the second screen and requires almost no effort to reach; the challenge comes in figuring out where all the coins and flowers in the level are.
What's more, stars are essentially your Hit Points, meaning that, while exceptions can be made, Hundred Percent Completion requires you to take no damage late in the level (when there are no more stars to find) or when fighting a boss. The original let you collect Star Cards, which could increase your star count any time outside of a boss, cutting the player some slack, but Yoshi's Island DS has no such thing.
The ending of Super Mario Land 3: Wario Land is determined by how many coins and treasures Wario has picked up during the game—specifically, this determines how big a castle he can buy. Finishing with 99999 coins and all the treasures results in getting the entire moon.
Super Mario Sunshine is probably the hardest 100% to get. Several stars are gotten in levels that can qualify as Platform Hell and That One Level, obtaining lots of Collectables that is a challenge by itself, and of course you can't get them all until you beat the game. Sunshine might even be harder to get 100% in than Galaxy 2 because of the very gimmicky FLUUD.
In Super Mario Galaxy, there are 120 stars, but you only need 60 to get to the ending. In fact, several stars are only available after getting the ending the first time. Furthermore, 100% Completion demands you to get all stars again with Luigi. After fighting the final boss again, you unlock Grand Finale Galaxy, for both Mario and Luigi. All in all, you'll have to beat the final boss four times before you're done, and collect a total of 242 stars!
Super Mario Galaxy 2 continues the trend. After beating the game, you unlock the World S. Getting all the stars and Prankster Comet stars across all seven worlds gets you 120 stars. You must then beat the game a second time to unlock the Green Star challenge, which gives you another 120 stars to collect. Then after that, you unlock the Grandmaster Galaxy, which contains the final two stars. Like the last game, there are 242 total stars.
Super Meat Boy has a percentage for each world. Getting 100% in a world means completing all levels (both Light and Dark Worlds) with an A+ rating, defeating the boss, getting all the bandages, and completing all warp zones. There's even an achievement for getting 100% on all worlds. The glitch levels don't count towards percentage, though.
An online game called Achievement Unlocked parodies this. There are achievements for things like pressing the space bar and dying. And the reward? Whatreward? The game was meant as a criticism of achievement mechanisms in games (the game's designer made a previous game with a very unsubtle crticism of upgrade mechanisms), yet it became popular exactly because people loved the achievements so much. The sequel made the "satire" tone a lot lighter.
Braid really has two levels of "100% completion," one of which is so secret that there aren't even any achievements for it. You do have to have 100% completion of the first five worlds (in terms of the 60-ish puzzle pieces, not of the various secret stars) to open the sixth, though.
The Loco Roco games have a goal of obtaining 20 LocoRoco in each level (which is tougher than it sounds), as well as excessive Randomly Drops-Level Grinding to completely build the MuiMui house.
One of the LocoRoco 2 unlockable levels seems to assume that people are going for 100% Completion, much like a Yoshi's Island GBA-exclusive level is (see its entry below). The goal is just downstream (really), while the challenge comes in Wreaking Havok upon realistic Jump Physics to obtain all 20 LocoRoco.
The Oddworld games give you a bonus ending if you save all the mudokons in the game.
World Of Goo has Obsessive Completion Distinction for individual levels and one cannot call oneself a true Goo Master unless one has achieved this on every level of the eponymous world and built a ridiculously tall tower in the sandbox environment.
Pokédex 3D Pro has an extensive list of things to do for completion - reading every entry, seeing every AR Code, finishing the 35 main quizzes, and remembering all but two of the Pokémon in one form or another in the quizzes. However, finishing the 35 quizzes unlocks another 34 to beat, each Pokémon has 4 aspects about it that can be remembered (appearance, entry text, cry, and type) with points for each, and how many quizzes you got perfect. In Japan, there are also passwords that can be used to unlock a few other things, including one of the two missing entries.
You get 100% (Burnout Elite) for winning all 120 events. Not that hard, just tedious. Your reward for that is gold paint on the "original" set of seventy cars.
You get 101% (Criterion Elite) for doing all of the above, and also for breaking every time and crash record of every road, smashing all gates, jumps, and jumps, and getting all fifty Paradise Awards in the game. The jumps aren't that hard to find (there are only fifty), but getting all 120 billboards require some leaps of faith across parking lots, very accurate jumping, and, in one sadistic case, very quick braking. And then there are the gates. There are 400 of them, and you can bet you'll get stuck on 394, trying to find the remaining six everywhere for days. Doing that nets you five carbon fibre cars (one for smashes, jumps, billboards, time rules, and crash rules) and platinum paint for the rest. For the extra percent, you have to do two complete sets of online challenges, with fifty in a set.
The same counts for bikes; 100% for all 38 events, chrome finish for breaking the time rules for both day and night for every road, and the extra percent for completing two sets of online bike challenges (five in a set).
And, for the truly masochistic, 102% for doing all five hundred challenges, getting 101% on the bikes and mainland, and 100% for Big Surf Island. Good luck.
The 102% finish is definitely a Luck-Based Mission since online players can be quite unreliable and difficult to rally into doing challenges. People can just sit on the map doing nothing, get lost trying to get to destinations, or just be a pain in the butt and attack other players trying to stick to the objective. Before an update to the game, if a player left during a challenge the whole thing would just end, adding another layer of frustration.
The Gran Turismo series of games is demanding enough to achieve 100% completion on, but Gran Turismo 2 was especially noteworthy—due to a rushed port job, it was only possible to recieve a maximum of 98.2% Completion on the official status screen! Sony fixed this, however, and offered replacement discs to people who bought the first run of GT2.
The Mario Kart series usually rewards you with extra karts, characters, and tracks when you start getting gold trophies in each cup. The series starts to ramp up the unlockables requirement by not only forcing the player to get star ranks in each cup, but players area also forced to do this for every cup in every engine class, which means you will be playing the same 4 to 5 cups at least 4 times each just to get everything.
Baroque (a strange sort of roguelike) has the item list which you fill up by giving/sending newfound items to the collector, you can save less then 15 items per tower run and the game has well over 200 items, and it's all random which ones you find in a given run, and even then, you still need to send up your badass gear since you need them to actually finish the tower. But wait, there's more! There's also Idea Sephira, which have a rare drop chance, in addition to counting as items, you can give it to the Baroquemongerer in order for him to add a line of fluff out of around 8 to whichever creature you dropped it from's "profile". Then of course, there are all the storyline videos, one of which there are three variations depending on how your first run ends, (clearing four levels of the dungeon, dying in the dungeon, or getting killed by pissing off an NPC outside the dungeon), and others depending on whether or not you flipped a heat switch regulating whether or not certain levels of the tower are frozen over or not. If that wasn't enough, there's the Baroques, Achievments for doing different actions in game, like clearing a certain point in the story, obtaining a certain number of items, not killing any enemy on a single tower run, includng stepping on the small bugs which can be hard to notice and harder to avoid, or doing absolutely nothing before you die outside the tower, (which means 100% Completion can be impossible for some due to a bug which causes the controller to move slightly), granted, you gain boosts to your stats from gaining theese achievments, but there are loads and loads of them... Now, if you thought, "Okay, that's it, atleast there can't be anything else.." then you're dead wrong, lastly, you have voices, yes, you can collect in the Database, (where everything is stored), certain select voice tracks by hearing them, some of these require quite alot of work to reach, and quite a few of them are missable, there are over 150 of them. Needles to say, it's impossible to manage everything in one playthrough, but everything carries over into a New Game Plus.
NetHack is a difficult enough game to begin with, but in addition it has conducts, which forbid key strategies in the game such as praying, reading, eating, and killling a monster directly. There is also extinctionism, in which you kill all of the monsters in the dungeon (they stop reappearing when you kill enough). 100% completion would be ascending while keeping all these conducts, achieving full extinction, and getting a final maximum score of 2147483647. This has never been accomplished and probably never will be (some have come close)
Guitar Hero and Rock Band usually require players to complete the entire tracklist in Career Mode so that the same songs can be eventually played in Quick Play, which is probably the most commonly used mode in both franchise. This gets pretty ridiculous in Guitar Hero 3 in particular, where not only is there no co-op quickplay option at all in the PS2 and Wii versions, the co-op mode has its own tracklist, with several tracks being exclusive to the co-op mode, forcing players to play through the career mode in co-op if they want to unlock all the music. Thankfully, the more recent games in each series have gotten a bit better with this, allowing players to play all songs in quickplay from the get-go.
Shoot 'Em Up
Sigma Star Saga would acknowledge if you had found all of the Gun Data when beating the game.
Air Force Delta Strike: Get all the endings and unlock all the bonus planes.
The Animal Crossing games have an in-game catalog of all the items you've obtained in the game, allowing you to buy most of them easily. Collecting all the items of a type puts a star on the catalog for that group- collecting every item is about the closest thing these games have to a main goal.
Not to mention the museum, or the town models.
Or what about having your freaking house paid off, completely. Having your town weed free for a month, or having your house given a perfect score for style? Most of these things give you furniture in the end, but for some people accomplishing them is its own reward.
In Roller Coaster Tycoon, if the player wins/completes all of the scenarios, a special, unbeforeseen park is unlocked.
Assassins Creed II has both the Monteriggioni value and the Synchronization stat; the former represents collectibles and progress. Scoring all the collectibles (all armors, weapons, paintings, feathers, etc.), clearing the story (to get the last assassination target portrait), and maxing out all the renovations to the town will result in the "Podesta of Monteriggioni" Achievement/Trophy (at 80% completion), a regular income of 15,000 florins every 20 minutes and a maximum of 60,000 florins that you can store. Synchronization on the other hand represents overall completion — which in addition to the above, and "synchronizing" with every Viewpoint, seems to require that you clear every possible mission, which may include the DLC ones.
In Hitman 2, completing missions with a perfect 'Silent Assassin' rating (normally by killing no one other than your mark(s) and firing your weapon only once) will grant you more impressive weapons as a reward, eg. a silenced version of the two silver hardballers that Codename 47 often poses with.
Hitman 2 only gave you bonus weapons for the first two missions that you complete with a "Silent Assassin" rating; Hitman: Contracts on the other hand, gave you a bonus weapon for every mission completed with the rating. A lot of these bonus weapons are pretty damn cool.
Metal Gear Solid 3: Snake Eater has two special items for the completionist in you. The first is the Infinity Facepaint, only awarded to those who finish the game with a perfect score or capture a small invisible animal and keep it alive until you finish the game. The other is the Stealth Camo, only rewarded to those who go through the whole game without killing anyone or being spotted or to those who can find 64 tiny, really well-hidden green frogs scattered around the game. There's also various camouflage uniforms that can only be unlocked by non-lethally defeating most of the bosses.
MGS2 has dogtags, with various unlockables tied to collecting them off of guards. Snake just gets the same bandana and stealth camo from MGS1 for the Tanker chapter, while the Plant gives Raiden, in addition to the same stealth camo as Snake, various colored wigs to wear, starting with a brown one (that gives infinite ammo) and ending with a blue one (that gives Super Not Drowning Skills) for collecting all 218 of them.
All Thief: The Dark Project and Thief II: The Metal Age missions track whether you have all the loot and all possible pickpockets; the latter also tracks whether you have found all the secrets in the mission.
"Down in the Bonehoard" has an optional quest to find all the golden bones and return them to their tomb. You are rewarded with some extra equipment.
"Return to the Cathedral" has a very difficult to avoid objective added partway through the mission; killing all the Hammer Haunts in the level.
"Strange Bedfellows" has an optional extra objective; if you kill any bugbeasts, then you have to kill all the bugbeasts in the mission, even if this means backtracking to the beginning of the level to kill the first bugbeast you encountered.
Partially averted in Thief II: The Metal Age, "Eavesdropping". You have to steal one of the keys lying around the level, copy it, and return it to its original location, but which of the (identical) keys is set randomly. Consequently, you do not want to collect all the keys before eavesdropping on the conversation that tells you which one you need...
Command & Conquer 3 has optional completion on every level for both completing bonus objectives, which are entirely bragging rights, and for collecting all the fun facts about the game world.
Fire Emblem had the Support Conversations page, which while you were working towards 100% completion, would reveal backstory of the characters whose supports you unlocked. The problem with this is that in order to fill the page to 100%, you'd have to play the game several times over, because each character could only have five support conversations in one playthrough. Not only that, but occasionally you'd be forced to pick a sub-optimal support to complete the page, thereby denying you the stat bonuses you could use. And in some games with this feature, there would be occasions where you could only pick one character and be forced to lose your chance at recruiting another.
Luminous Arc 2 got this, with guild missions, Final Intermission CGs, as well as the Hot Spring Intermissions...
In Medieval 2: Total War, completing the Long Campaign is basically the highest achievement you can get, it involves taking over about one third of the known (at the time) world, and as a reward you get a victory cutscene. However it is possible to continue playing, and take over the entire known world (this takes a LONG time), and what do you get for this? Nothing, the game just keeps going, but with no-one left to fight. Oh the futility of war.
In Resident Evil 3 Nemesis, collecting every single file in order grants the Jill's diary, a secret file that explains some of the events that occurred during the Time Skip. Annoyingly, each file has to be read as soon as it is obtained to get this.
However it's incredibly easy to screw this up due to optional paths and a room containing two files at once, with no indication of which one comes first.
In Siren, getting 99% completion of the archives (which aren't actually listed as a percentage, but there are exactly 100 entries in the archive, leading to the same effect) unlocks two extra videos. One of them is just a filler that shows what one of the characters was up to during a gap when we didn't hear from her in the course of the normal game... but one of them gets you 100% completion and shows the event that caused everything that happened in the game. And getting 99% completion is basically impossible without a guide, as archive items are hidden throughout all the game's stages, and sometimes don't stand out, or require you to do odd things to find them.
Third Person Shooter
Destroy All Humans has a completion percentage. In the first game, 100% completion is nearly impossible, because it requires searching for probes scattered around the landscape, which don't show up on your radar. In the second game, completion is possible, but what happens when you finally reach 100% completion? Absolutely nothing.
Gears of War 3 takes this to absurd levels. "Seriously 3.0" requires the player to reach level 100 and get every gameplay medal at its maximum score. Note that some medals require achievements on certain difficulties that Xbox Live public matches don't support. For example, the "I'm a Beast!" medal requires the player to succeed on all 12 waves of Beast Mode on Insane difficulty—but only Private matches can have their difficulty set to anything other than "Normal." On top of this, the player must also get 1000 kills with all six starting weapons, 500 kills with every other weapon (VS matches only. Campaign and Horde do not count), win 100 matches of Capture the Leader as the Leader without ever getting captured once, complete every non-PVP gametype on the highest possible difficulty, and more-or-less master every game type. Oh, they must also play as a female character in 500 matches.
Visual novels generally at least allow the player to unlock CGs in a gallery section as they are encountered in the game, requiring the player to seek out all the branches in order to clear them all. Sometimes there is a completion percentage, other times the player makes do with simple blanks. Unlocking all the CG usually doesn't do anything else. Unlocking enough (or all) of the Multiple Endings, however, usually does.
Aoi Shiro's image gallery helpfully gives the percent CG collected for each character and overall. Another screen keeps track of all the endings by marking them with pearls as they are reached.
The first Galaxy Angel had, along with a set of CGs for every available girl, a secret set for Shiva, which accompanied The Reveal of the true identity of the White Moon's heir. Of course, getting them all made the next game make a lot more sense, as Shiva's secret was common knowledge in the game by Moonlit Lovers.
Fate/stay night keeps track off the (numbered) bad ends with tiger stamps. Collecting all the stamps and completing all the endings nets you a short video and a new title screen. But getting the bad endings is its own reward anyway.
In Katawa Shoujo, to get 100% completion you need to fill up your library with every scene possible. If you complete it, you are rewarded with an extra CG in the gallery with a simple picture of the six girls and a thank you for playing the game.
Reaching all the endings in Tsukihime unlocks the epilogue 'Eclipse.'
In Marvel Avengers Alliance, five-starring all missions in a chapter gets you the powerful Golden Weapon for that chapter. Also, completing every fight and deploy in some missions gives you access to an Epic Boss which when defeated offers a chance at strong weapons/gadgets and more Command Points for unlocking characters.
Mass Effect has Achievements (see Xbox 360) that provide hidden Gamerpics or damage bonuses with certain weapons.
Specifically, there are the "Completionist" achievement (acquired by completing most of the game — not actually 100%, but including most of the sidequests), and the six different ally achievements, which require you to have a particular character in your squad for almost all of the game. The achievement for Liara is particularly tough to get, since you have to deliberately avoid sidequests in the early part of the game so you can advance the plot enough to rescue her first, then go back and do the quests you avoided once you have her on your team.
Of those six ally achievements, the Arbitrary Headcount Limit will likely prevent you from achieving more than two at once, meaning you'll need at least three playthroughs to get those. This is just as well, since you'll need more than one playthrough in order to get the Power Gamer achievement (reach level 50) and likely more than two to get the Extreme Power Gamer achievement (reach level 60). The game does have New Game Plus, but there are also achievements for heavily using certain abilities which aren't available for all classes. You'll probably need to play through the game at least four or five times in order to get all of the achievements.
Even aside from these metagame achievements, there are several in-game Collection Sidequests that require you to visit a large fraction of the explorable galaxy and often go out of your way when exploring uncharted worlds in order to complete them. Similarly the "Scan the Keepers" sidequest, which while confined to a single large space station, requires exploring nearly every nook and cranny of said station.
Wide Open Sandbox
Grand Theft Auto games often give neato whiz-bang prizes for completing 100% of all the optional tasks, tests, and races. All the required tasks for plot completion total around 20%. In Grand Theft Auto San Andreas, the player's childhood home in Ganton is upgraded with spawns for a Rhino tank and a Hydra jump jet.
In Grand Theft Auto Vice City you get infinite ammo, upgraded health, maximum armor, the ability to recruit two gang members and a t-shirt that says, "I beat Grand Theft Auto Vice City and all I got wasthis lousy t-shirt." Oh, and an easily accessible Hunter helicopter - toughly armoured and armed with infinite double missiles and a chaingun.
Getting this in Just Cause 2, in the PC version at least, is actually impossible; the game keeps track of the innumerable number of things you've done out of the innumerabler number of possible things as a percentage, but it seems that the tasks really are innumerable, because truly obsessive players have discovered that the game crashes when it tries to load saves that are within a few tenths of a percent of 100%.
Going so Over the Top in this regard it's not funny, No More Heroes for the Wii features a set of "trading cards" that the player can collect. There are 50 cards on the first run through of the game, each bearing the picture of a wrestler's mask. There are in reality a total of 150 cards in the game, which must be replayed a minimum of three times from clear files to achieve 100% Completion. This fits in with the game's over-the-top nature, as the "hero" is a obsessive otaku.
The reward for 100% completion in Red Dead Redemption...is clothes. Specifically, it's a Government Agent suit, which lets you do anything you want without being attacked by cops. However, that doesn't stop the citizens from firing back.
Scarface: The World is Yours needs you to buy all the Exotics, collect all the Femme Fatales, wiped out all the gangs in Miami and completed the extra missions on the Islands. Fortunately, there is no need to pass all the races. Achieving this let Tony summon the Femme Fatales as bodyguards.
Subverted in The Path: It isn't possible to collect all items on any run-through with any single girl, and because some events unlock items and events only accessible by another girl, it's not possible to get 100% completion on the first complete playthrough. And even after collecting all secret flowers and inventory items, visiting every site, unlocking every secret room, and encountering The Wolf with all girls, the player is rewarded with a purely arbitrary, semi-random letter grade between D and B...you can never get an 'A' and there will always be some items counted as not discovered.
The Trophy system for PlayStation 3 games (which works similarly to Xbox 360's Achievements) has a whole tier—Platinum—that represents collecting every other trophy in the game. In some games, there is a separate trophy for completing 100%.
Achievements in Xbox 360 games can be completely ridiculous. For example, 100% Completion of the Achievement list for Gears of War required you to get 10,000 kills in ranked matches to get the "Seriously..." achievement. The sequel increases the number to 100,000 but makes it much much easier by letting you get your kills in campaign mode.
Note that some Achievements are nigh-impossible to unlock. See the previous entry on Gears of War or see why Rock Band is the trope namer for Bladder of Steel.