A playthrough of a game with the intent of completing it as fast as possible for the purposes of entertainment and competition.
There are two types of speedruns: "regular" and "tool-assisted".
Regular aka Realtime - Consists of a player sitting down with an actual copy of the game and playing it normally, using only whatever features are available on the original hardware. The clock starts ticking at the beginning of the game and doesn't stop until the ending is achievednote The exact timing varies between games and even between speedrunning communities; some begin at the moment the game boots and others the moment the player pushes start, for example.
Some regular runs are Segmented. Each segment consists of a level or group of levels. Instead of playing the entire game in one sitting, the player is allowed to get the best time possible for each segment, retrying each segment as much as desired.
Sometimes, emulators are used, but only for the purpose of actually playing a game as opposed to using any of the available tools, aside from possibly any recording functions they may have. For segmented runs, some players may only use save states between segments as a method of saving time.
Tool-assisted - Use emulation to play the game frame-by-frame to create the optimal time possible, often exploiting glitches and manipulating random events along the way. While they are technically possible, they will use methods that no one has the reflexes or timing to pull off with any consistency in real-time, and some of them will use control inputs that would not be available on a normal controller, such as left and right on the d-pad at the same time.
In both versions, Sequence Breaking, route planning, and tight play are the key. Exploitation of Good Bad Bugs may come into play, particularly in tool-assisted runs, which can make a game's protagonist look like a Reality Warper. The notion of completing a game as fast as possible is frequently an example of Emergent Gameplay (excluding those games where speed is the whole point, such as racing games).
There are also three subcategories: "100% run" (where the player tries to collect everything in the game as quickly as possible), "minimalist runs" or "low%" (where the player must skip all non essential items while still completing the game as quickly as possible), and the "pure speed run", also known as "any%" or "fastest time" (where the player skips as much of the game as is needed to achieve the best time). Many a popular Self-Imposed Challenge are also up for grabs.
Speedruns are usually created as an attempt to show off one's skills, while still providing an entertaining video. (Most speedrun compilation sites have a requirement that the run must be reasonably entertaining, and under a certain length [usually 7-8 hours, with many being just a few minutes], to be accepted.) They are not for people who want to enjoy the plot or explore the world. Due to the many methods used in speedruns, and overall design of different games, it is not a good judge of how long a game is for the average player at all; for instance, there could be exploitable bugs that are only possible to pull off in a Tool Assisted run, and others that can be done in realtime with only a great deal of dedication, skill, and luck. A specific example of this: some Tool Assisted runs use glitches that require hitting left and right at the same time, or up and down at the same time; those ones are basically impossible on any standard unmodified controller. The optimal path can be radically changed at every step based on whether or not these bugs are used.
Some series that are popular for speedrunning are Quake (the series which arguably started competitive speedrunning), Doom, Metroid, Super Mario Bros., The Legend of Zelda, and Mega Man.
One of the most popular "regular" speedrun archive sites is Speed Demos Archive. For tool-assisted, technically perfect runs, try TASVideos. For speedruns and speedrun races performed live for your viewing pleasure, head over to SpeedRunsLive.
(Note that comparing the times of unassisted and tool-assisted speedruns has a small caveat. The timing of unassisted run generally starts from when the player first gains control of the playable character; any time spent in the game startup screens and menus before the gameplay starts is not counted into the length of the run. However, tool-assisted speedruns are counted from console power-on. This may add several seconds to the run's length that wouldn't be added in an unassisted run. This can cause some unassisted runs to seem closer to the time of the tool-assisted equivalent than they really are. The world records of Super Mario Bros are good examples of this.)
Luck Manipulation Mechanic: Speedrunners find everything they can, intentional or not note though keep in mind that unintentional examples should not be added to that trope's article, as long as it ultimately saves time. TASers can make their own luck, though they might have to burn a few frames putting in inputs to get the exact outcome they want (accounting for whether those few frames will pay for themselves later is an oft-complicated process).
No Death Run: Simply avoiding death tends to be a large factor in completing Nintendo Hard games quickly; in games where dying saves time, "without deaths" is often treated as a separate category.
Not the Intended Use: Most tricks used in a TAS run are physically impossible to pull off without the use of an emulator note this can mean frame-perfect timing that real players could never pull off, or actually impossible actions for a standard controller such as pressing up and down at the same time, which of course the game designers never predicted.
Pause Scumming: for TAS players; some games are still active when paused allowing for random number manipulation, or a meta example of rapidly pausing the emulator. Depending on the game, some realtime runs can also make use of this, such as frame-buffering techniques in The Legend of Zelda: Ocarina of Time or the infamous pause damage glitch in MegaMan. The dominant rule in TAS is that the real time is what counts, while a better in-game time is secondary; that said, there are moments where due to in-game slow-down, the player can pause for a frame or two to make the in-game time better without affecting the real time negatively.
Doom has a large speedrunning community and a large range of different categories, from the standard affairs such as UV-Speed, NM-Speed, UV-Max and NM-100S, and then absolutely crazy challenges such as UV-Tyson, where you have to do a UV-Max run, but with the restriction that you can only attack with the fist, berserk fist, chainsaw and pistol (and telefrags) - seems reasonably challenging at first, until you realise it also includes levels such as Tower of Babel...
This run of Super Mario Bros. 3 is one of the most famous tool-assisted speedruns of all time. When it first started making the rounds it was not initially advertised as being tool-assisted, which led many gamers to decry it as "fake". It has since been obsoleted by more than 35 seconds, but is still a good example of its type.
Speaking of SMB 3, it's not only possible, but very easy for a moderately skilled player to finish the game in approximately twenty minutes if they know what they're doing. It requires the player to beat the first three levels of the game, the first mini-castle, and six more levels (in World 8). Not dying helps, but twenty minutes is if you take your time.
Then there's the quad-run TAS of all four Super Mario Bros. NES games (original, Lost Levels, 2 and 3) with a single controller input (similar to the Mega Man example below), and it's still faster than the above-mentioned SMB3 run by Morimoto. Pressing left and right together makes Mario move to the right in some of the games but not others, a "feature" that makes such a slick quad-run at all possible.
The nightmare difficulty for Quake, beaten in just under 20 minutes (a world record). Quake is one of the most-run games of all time, so the route and performance is extremely optimized.
Even better, a run a few years back smashing that to pieces with a Nightmare run in 12:23. The run is a segmented run, however, and while still talented, is far better than could be expected of a straight playthrough.
The above is just one product of the very active Metroid speedrunning community. Among other things, every 2D game has now been beaten in less than an hour (Metroid II: Return of Samus was the last to fall). Here are a couple of the all-time classic runs:
The description of the tool-assisted run which collects exactly zero stars covers the history quite succinctly:
"At first there were 70 stars because Bowser demanded it. Then there were 16 stars because MIPS the rabbit demanded it. Then there was 1 star because Bowser's Sub demanded it. Now there are none because the viewers are impatient and demanded the game be quicker."
There's also this speedrun, utterly demolishing the previous video's time in 4 minutes and 19 seconds.
Mirror's Edge has this as a game mode. It even has achievements for it, and features the nigh-impossible task of completing the second level, Jacknife, in under 11 minutes. This mission takes 20 minutes on the first try. Have fun!
This has understandably become almost a sport in the Sonic the Hedgehog series, with the record time for the entirety of Sonic the Hedgehog 2 being 18 minutes and 12 seconds, and Sonic 3 & Knuckles being almost completely broken by tool-assisted speedruns.
Sonic 1 on the Genesis/Mega Drive can be beaten in less than 21 minutes, real time. Green Hill Zone Act 3 in particular is pretty funny. The huge time bonus for clearing an act in less than 30 seconds is a factor; for a couple acts it's faster to avoid it.
In Cave Story, the final Sacred Grounds level includes an on-screen timer (if you find a special item), which has the sole purpose of encouraging people to do speed runs. Various bonus pictures are shown if the player completes this within a certain amount of time. Despite the excessive amount of enemies and hazards and several gates that take five full seconds to open, people have been able to complete the level in mere minutes.
Iji also includes a timer for speedruns, and when new features are added, the author usually makes sure they won't affect speedruns. For example, skipping the fight with Krotera (possible from version 1.3 onwards) forces Iji to give Vateleika (offscreen) a ten-minute head-start, so speedrunners will fight instead.
It's possible (if you know the solution to the final two puzzles) to skip just about everything in Myst. You can start a new game and be watching the ending in under a minute. Naturally this kills most of the replay value to the game, which is why the game is the only one in the Myst series to get an Updated Re-release which adds some new stuff (but it doesn't change the way to get to the ending, unfortunately). Later games in the series actually required you to do the whole game.
Using a save file from Saga Frontier II, it's possible to get an extra weapon in Legend of Mana and break the rest of the battles wide open. This weapon can allow you to beat the final boss in 8 seconds.
A popular activity among Rubik's Cube fans is "speedcubing," or solving the cube as fast as possible. The world record for a 3x3x3 cube stands at 5.66 seconds.
There is also a tool-assisted run of Rubik's World for the Nintendo DS that beats the world records for 2x2x2, 3x3x3, and 4x4x4 cubes.
Sport stacking is a similar activity, in which you stack cups into a specified stack as fast as possible.
Kingdom of Loathing's New Game+ style of play allows it to be one of the few MMORPGs that allows for speed runs - from level 1 to defeating the Naughty Sorceress, in as few adventures as possible. Players compete, share notes, and obsess fiercely over shaving adventures off of the top time. A truly speedy speedrun usually involves skills gained from 30+ ascensions, ultra-rare or archaic items, plans mapped out well in advance, and $20 or more donated to the game.
Hardcore speedruns remove the advantages of items and donations, but still require permed skills from many Hardcore ascensions, as well as tighter planning. Luck doesn't hurt, either.
They only remove the advantage from donation equipment, you still need the familiars and skills just as much if not even more so.
Bad Moon speedruns do put everybody on a pretty equal footing, by temporarily stripping you of those familiars and skills. There's a guide out there for reliably doing one in 12-14 days. (To compare, a 1-day speedrun has been done in regular play, though luck was a significant factor, and there are people who consistently do 4-5 day runs in Hardcore.)
The level of obsession this involves can get downright frightening. Some players (affectionately known as "dickstabbers" from a comment Jick once made) have managed to shave their times down to two days for a Hardcore run. These also tend to be the same players who throw royal fits if any change in the game adds a single-digit number of turns to their runs. They aren't very popular.
Half-Life in Half an Hour uses the "exploiting glitches" method, and also uses such tricks as trapping a scientist in a door to stop it from closing all the way and using grenades to power jumps.
ThisHalf-Life 2 speedrun is notable in that... well, just read the comments. It exploits glitches just like Half an Hour, including bonking people with objects to make them teleport, and jumping off items you drop and grab below you to fly. Probably the best part is flying over the entire Ravenholm minus the mine area in 30 seconds, never seeing Father Grigori. A similarly wacko bit is the "Water Hazard" chapter; Gordon ditches the speedboat halfway through and glitches his way through a few miles of radioactive goo just so he won't have to wait for NPCs to attach a gun to the boat, and when the climactic battle against the chopper begins, he leaps over a dam and runs away to the next area.
Castlevania games have generally been very good for speedruns that go ridiculously faster than an average playthrough, but even the series' general high level of breakage in runs was dashed to pieces with this TAS run beating Harmony of Dissonance's Maxim mode in under 23 seconds.
This run shows that it is possible for a very good player to complete Maxim mode in less than a minute with a different route and knowledge of the game's quirks.
ThisAria of Sorrow run demonstrates the power of luck manipulation in tool-assisted speedrunning; by creating a speedrun frame-by-frame, it's possible to ensure that the Random Number God always gives you the correct number. As a result, this run completes the game while collecting all 120 of the souls — normally very rarely occuring random drops — in 24:56!
Here's both loops of the notorious Nintendo Hard game Ghosts N' Goblins being completed in just under 23 minutes. And here's its Super Nintendo sequel—again, both loops—in just over 42 minutes on its hardest difficulty.
Final Fantasy IX actually rewarded the player for doing a speedrun. Getting to a certain area in the final dungeon in less than 12 hours will net you an Infinity+1 Sword.
The Mega Man series is also notable for speedrunning. As seen here, assisting with tools can make 1 unrecognizable from its former self.
There seems to be a small trend where people try to see how fast they can beat more than one game at the same time using the same controller. Here's a TAS that features a guy beating Mega Man X 1 and X2 in about 40 minutes and another where two guys beat Mega Man 3 through 6'' in about the same amount of time.
The Mega Man X/X2 run has been obsoleted by this, a 100% Completion of Mega Man X, X2, AND X3 using one controller's input.
Time attacks on 9 are pretty impressive too as seen here. Due to weapon balancing, every weapon comes in handy even outside the boss fights, some of which are used more often and others less.
Mega Man 10 features time attack leaderboards and the ability to view the replays of any of the top ten times from any stage (or the whole game) from inside the game itself.
The Speed Gamers are a group of people who perform live, consecutive speedruns of all or most of the games in a given series. Their speedrun marathons occur about once a month and are usually used to raise money for charity. You can check when their next marathon will be on their website.
Instances in World of Warcraft sometimes have quests requiring you to finish them or reach a certain point within a time limit, meaning that Speedruns are an actual programmed part of gameplay.
Not just the quests: in some of the earlier instances, most notably the Scarlet Monastery, respawns are a problem for groups that take their time, especially in the Cathedral wing, where patrols can pop up at inconvenient times. And the deity of your choice help you if you all die on the final boss, chances are all the mooks you killed on the way got better.
The first raid instance of vanilla World of Warcraft saw a bit of a speedrun war break out. A Norwegian guild posted a speedrun of Molten Core being clared in 1 hour and 35 minutes. Another guild saw that and decided to do it one faster, clearing it in 1 hour and 22 minutes. Cue the Norwegians to up the ante, reducing it to 1 hour and 10 minutes. And this when 1 hour was considered reasonable for clearing the first two bosses (1 hour being respawn time of the trash leading up to it).
More recently, several achievements exist for completing all or a certain part of a dungeon within a time limit, such as getting from the first boss of Heroic Oculus to the end within 20 minutes.
Challenge Mode is entirely based around this. Completing the dungeons within the time limit will unlock special rewards, such as mounts and armor that can be transmogrified.
On the topic of MMOs, Warhammer Online often has fast respawn timers on Player Versus Environment enemies, good if there's competition for said monsters, but you'd better hurry up and grab/kill what you need before they're back if you're 1) alone and 2) squishy. A respawned monster can easily take out a Bright Wizard or Sorcerer who's already in a fight.
Eversion switches to a time attack mode after you clear all the worlds. Additionally, the game starts doing a self-parody of the creepy messages that sometimes replace the "READY!" screen in worlds X-7 and X-8, with messages like "GO!", "HURRY UP", "GAME ON", and "READY! TO RACE".
Ace Combat has various Scrappy Levels where you have to take your plane through an enclosed area. So, naturally, people took the fastest plane available and went in with maximum power. Like taking "Greased Lightning" from 2in the X-29 or "Aces" from 5in the MiG-31.
One runner took it upon himself to run the PS2 games in one sitting (on Very Easy, but still!), beating 04 in 2:29:30, Zero in 1:20:38, and 5 in 3:56:54.
Punch-Out!! attracts many speedrunners, as the mechanics of the game (specifically, the patterns and weaknesses of the enemy boxers) allow for much probing of the system. Super Punch-Out in particular, due to the minor differences in system compared to the previous games, has had speedrunners get times on nearly every opponent down to ten seconds or less. Nick Bruiser, the final boss, in 9.98 seconds. (There's a faster one on YouTube, but its legitimacy is questionable.)
The Metal Gear Solid franchise also attracts a variety of speedrunners. Some examples include:
Braid features this built into the game itself - in addition to having several timed segments of the game with par time and leaderboards, getting the final achivement, "Speed Run", involves completing the entire game in under 45 minutes. (Including the ending.)
Unlocking one of the challenge rooms in Spelunky requires beating the game in 10 minutes or less. The game can be beaten much faster than that, though that takes at least as much luck as skill.
Reaching Scenario 28 in Super Robot Wars Compact under 250 turns unlocks Shin Getter Robo. Also, if you clear a scenario in less than 11 turns, you can give a skill to one of your pilots.
Speaking of short tool-assisted speedruns, there's the entire Pokémon Yellow speedrun with 152 Pokémon caught within less than 90 seconds and with mere seconds of in-game time and by throwing away entire floors. Honored for their exploits indeed.
This tool-assisted run skips even that, reaching the ending in three and a half minutes by abusing sub-frame resets to turn save corruption into a science.
NASA's free gameMoonbase Alpha is pretty-much a whole little multiplayer game built around the concept. The team of players has 25 minutes to repair the damaged life support systems of the lunar colony.
The fastest speed run of all time (On SDA) is actually Clue, coming in at a time of three seconds. By the time you finish reading this, you could have already watched the run in its entirety.
The speedrun of the PC version is now the fastest, clocking in at a mere second!
Some TAS runs get a bit ridiculous thanks to the ability to manipulate the game's memory directly to take the player right to the ending note but TASsers can not just decide to alter the memory from the emulator; instead, they must find a glitch in the game that alters memory, then find a way to get that glitch to specifically change what needs to be changed to trigger the ending. Demonstrated to great effect in the current standing runs of Pokémon Yellow version (1:09.63), Super Mario Land 2 (2:08.98), Super Mario World (2:36.40) and Kirby's Adventure (0:35.91).
A 43-minute world record run of the original Deus Ex (on Realistic difficulty) exploits a number of bugs and shortcuts (grenade jumping, skipping the entire first mission, glitching JC's weapons into a prison cell so he can retrieve them immediately afterwards, physics exploits, etc.) and the open-world nature of the game to get past situations that would stall most other players. The end result is that JC Denton skips most of the boss encounters, never deactivates his killswitch, has conversations with people he's never met before and blows himself up into Ludicrous Gibs right before hightailing it out of Area 51.
This speedrun of Arcanum uses a lot of Sequence Breaking. It involves killing Stringy Pete, who is widely considered to be the most difficult fight in the game, within 4 minutes of starting the game.
Here is a TAS run of the SNES game based on the Biker Mice from Mars show. Possibly the fastest we'll ever see Vincent go.