"I mean, there's a reason the expression 'needle in a haystack' is used for a hopeless task no one in their right minds would undertake unless they had hours to while away in mindless drudgery. An excellent adventure game has no haystacks. A good adventure game probably gives you a magnet. A bad one makes you look at straw for seven hours. This game is nothing but haystacks, and sometimes the needles are made of straw."
A Pixel Hunt is an annoyingly common Fake Difficulty of graphical Adventure Games, where a hotspot or object that the player has to click on is only a few pixels in size, and hidden in the scenery. Since many such games do not tell you what is under the mouse cursor until and unless you actually click on it, this can make for frustratingly lengthy searches, or Guide Dang It moments if the player never realizes there was an object to begin with, and thus can't solve the next puzzle. Also known as "pixelbitching".
Greg Costikyan discusses this in his article on game design "I Have No Words and I Must Design":
Or let's talk about computer adventures; they often display information failure. "Oh, to get through the Gate of Thanatos, you need a hatpin to pick the lock. You can find the hatpin on the floor of the Library. It's about three pixels by two pixels, and you can see it, if your vision is good, between the twelfth and thirteenth floorboards, about three inches from the top of the screen. What, you missed it?"
Metroid: Other M has several forced first person segments, where you're trying to find one small detail in a much larger picture. The two most egregious examples are The cybernetically enhanced Zebesian, where you have to find the small Galactic Federation logo on its chest, and are given no hints about this, and after finding Lyle's body, you have to turn around and look at a spot of green blood, again without hints Worse yet, you have to spot it on a field of green grass. It's hard enough find the spot without it blending in with it surroundings. And even more worse yet it happens while all the soldiers are remarking how notably gruesome his death was while standing in a way that obstructs your view of the body, while the natural response is to find a way to move the soldiers or find some way to examine the single most striking thing in the area... the game wants you to completely turn around and look at an odd puddle.
Other enjoyable hunts include spotting brown grubs against a brown background, spotting one moving leaf among a whole forest of leaves, and spotting a bridge that is ABOUT to be burned down.
There's also a fun one at the end of the game, which, while obvious in hindsight, can be counter-intuitive the first time around because it averts one of the usual conventions of gaming, to wit: You have to target MB rather than trying to dispose of her minions first. Made all the more confusing by the fact that said convention was in full force for the previous boss fight, where you have to kill all the small metroids before you can damage the big one. Considering her massive minions are right in your face the whole time (and do take damage, but never seem to die) and she's way in the background), and attack you viciously, it's a particularly mendacious example, as the game uses intentional trickery to misdirect you from thinking it's even a Pixel Hunt at all.
In Assassin's Creed II, Subject 16 encoded data which you have to decode with Pixel Hunt puzzles by finding either Pieces of Eden in historical photographs or Renaissance paintings. At least in the paintings you are trying to find something which was already in the painting (a staff, a sword, etc) which can be recognized. In the photos, you are looking for a little sphere the devs added and thus have no frame of reference. Just hunt and peck.
Mr. Little from Cave Story is exactly what his name implies, at only five pixels tall. What's worse is that he's wearing green, and standing in grass that's about the same shade and height. At least he walks around. If not for his family, located elsewhere in more conspicuous surroundings, you would never know he was around. Fortunately, he is not needed to advance in the game. You need never even realize he exists.
Parasite Eve suffers from some incredibly obnoxious moments where the player simply has to "search the area for clues" or some such. Often the player can search the same object three or four times without triggering a necessary cutscene because Aya has to be facing just so and interacting with the exact right pixels. Worse was the fact that you couldn't run and search at the same time, so button-mashing a search ended up with Aya's running animation going on and off like a strobe light.
The World Ends with You kinda uses this during the battle with Tigris Cantus. At one point, she deactivates all of Neku's pins, turns invisible on a white screen while she summons illusions of herself, and equips the player with only the Rhyme pin. You need to find a tiny little yellow glint to attack so that you do damage. Luckily, you can track said glint by examining the direction of the player character's shadow.
Mega Man Battle Network has a number of invisible items, usually key items, such as "Dentures", "Beetle", or "Firewood" that require a bit of pixel-hunting.
While not necessary for completion, finding the Daredevil and Black Panther action figures in Marvel Ultimate Alliance (which are required for unlocking the respective characters) can turn into this. Both are fairly dark and can end up being near-invisible in levels like Mephisto's Realm.
Avalon Code is ridiculous in this regard. If you want full points on a map, you'll have to run around frantically pressing the A button at every suspicious nook, and you also need to do this in areas where there's enemies, which means that pressing A instead causes you to attempt to uppercut a nonexistent enemy every time you press it and aren't close enough to a piece of scenery that you can examine.
A less onerous example comes in Fallout 3 and Fallout: New Vegas. Plot-critical items are rarely difficult to find, but some switches, doors, or bonus items can very easily blend into the Real Is Brown background and assorted junk. This gets extremely annoying when they are laying amongst owned items, and it can take a minute to find the exact angle to avoid stealing someone's toothbruth and being attacked.
The first Diablo did not have the key that highlights all items on the floor. Good luck finding that tiny ring. This was so frustrating that the third party Hellfire expansion added both a spell and a character power to illuminate all items.
King's Quest IV: the bridle on the island, and the gold ball under the bridge.
King's Quest V is rife with these. Examples include the locket, the crystal, the piece of cheese, and probably several others that my memory has suppressed. It also includes an actual, well, needle in a haystack. Luckily, you don't have to hunt the pixel to get it, although some people doubtless tried.
King's Quest VI contains a one-pixel coin you have to find. This is actually easy because it has an animated sparkle every few seconds. It turns out the harder pixel hunt on the panel was a board that managed to blend perfectly into the scenery; after the coin fiasco, who would look at it?
Space Quest 6: Roger Wilco in The Spinal Frontier made by the same company lampshades this by having the narrator comment on a certain very small item when you look at it by saying, after identifying the item, "Good eyesight! Now we'll have to do one of those puzzles where you have to find a one-pixel coin or something. But hey, who'd design a mean, unfair puzzle like THAT?"
There is a library filling five to ten screens, in which three individual items labeled "book" have to be found in a large generic mass labeled "books". However, it at least has a command ("What is") that displays item names when hovering the mouse over them, even before a click.
Even worse is right near the beginning of the game, where you need to find a piece of "sticky tape" stuck to a fallen bookshelf, as said object is only a few pixels wide.
There's a puzzle towards the end that, initially, can seem even worse. Just like in the movie, the buzzsaws in the Grail temple have to be passed by kneeling...however, there is no "kneel" command. The actual solution is to click the walking cursor on a small, specific patch of ground when trying to pass through the trap's trigger zone; while this seems like unfair pixel hunting at first, it's actually a meta-puzzle. The game comes packaged with its own Grail diary, a booklet containing veiled hints on a number of game puzzles; one of the drawings in the diary is an illustration of the tunnel floor, with an X mark clearly indicating where to stand to avoid being decapitated. This is meant to be a parallel to the movie; just as Indy uses his father's diary to solve puzzles throughout the movie, the player is meant to use the diary booklet to assist in their own puzzle-solving. That doubled as a brutal piece of Copy Protection, if you gave up too quickly.
Fate of Atlantis has one scene that Subverts this. When Indy searches an underground dig site in the Egyptian desert, it's pitch black and everything is labeled "round thing," etc. If the player waits, Indy's eyes will adjust to the darkness and the puzzle becomes much easier to solve.
Pretty much anything in Fascination.
Torin's Passage, a Sierra adventure game developed by Al Lowe, featured one scene with this trope implemented quite literally; it involved locating a pixel-sized glint that occasionally flashed on the screen, and in the middle of a maze, at that. And the game's hint system was no help; it merely told you to look for the glint on the screen...
The game also had another example of a pixel hunt; at another point there is a moss-covered slope that is extremely slick (and yes the game does use the associated pun), and if you attempt to climb it you fall off and die. You can enlist the help of the nearby grass to tell you places that are safe to go to, but grass only tells you where a safe spot is while your cursor is on it, and the safe spots are ludicrously small as well as visually indistinguishable from the rest of the slope. Add this to the fact that you had to find six or seven spots to cross the slope, constantly assaulted by the grass's high-pitched cries of "not there" and "no", hoping for the occasional "yes", it made for an extremely frustrating experience. Al Lowe has no idea how to play Hot and Cold, apparently.
A review showed a screenshot of this game captioned, "See that wrench? Neither did we. For three hours."
In Maniac Mansion, if your character is captured, the cell door can be opened by pushing a particular brick - one in a wall of hundreds. This one's pretty easy though, considering the (primitive) engine makes every hotspot at least 8x8 pixels in size.
The Monkey Island series has some fun with this trope. But like all latter-day LucasArts games, it displays item names when you hover the mouse on them.
In the first game, you're required to get a rubber chicken to go somewhere. The problem? It blends in with "cursed" chickens the player character says something to the effect of "I'm not going near those" if clicked on the wrong one. Thankfully, this was fixed in the special edition.
In the second game you are, at one point, completely in the dark. It turns out there's a light switch on the wall. The problem is, both the room and the switch are completely black, and thus invisible.
In the hard version of the second game you at one point have to pick up a piece of string that blends in perfectly with the mise-en-scene.
In the third game, if you carefully move your cursor over every pixel in the Plunder Island beach area, you can locate a "secret button" hidden inside a column on a bridge. Pushing this button remotely activates the nearby fort's cannons, which is absolutely useless but, according to Threepwood, "fun".
Also in the third game, repeatedly using the beach water on Blood Island will make Guybrush get in, and appear in the water scene from the first game. You only get a brief look before Guybrush comes out again. Afterwards, you can click on a certain spot in the water to go under and have a proper look. There's only about a 3 pixel square to click on.
There's a lucky penny hidden on Lucre Island in the fourth game. You have to run to an area of the city that you've got no business being in and carefully walk around until Guybrush is standing right next to it, facing in exactly the right direction. It's been glued to the ground.
Towards the end of Full Throttle, not only do you need to find a tiny little spot on a gigantic rock wall to kick so you can open a secret passage, you have to kick it at just the right time. So you'll be kicking the wall all over the place and still not knowing if you're kicking the wrong spot or if you just haven't gotten the timing down.
The fluff makes the clue particularly unhelpful — Mo mentions that she used this guideline when she was six, so you're trying to kick spots on the wall where the crack matches the eyeline of a little kid. The crack that's supposed to point you at the right spot to kick lines up with your own, grown-up, six-foot-tall eyeline.
The The X-Files Game had a required clue in the form of a bullet that was 2x2 pixels big (in a game that ran at 640x480), making it probably the most egregious example of (quite literal) pixel hunting on this list.
Clock Tower aka Clock Tower: The First Fear had the cursor change from an arrow to a target box whenever it was moved onto anything that could be interacted with.
The Polish game Kajko i Kokosz has many occurrences where you need to pick up a very small item which doesn't at all stand out against the background. For instance, you have to pick up a stone hid among a stack of identical stones. Or you need to pick up a black rock... which is 1 by 1 pixels big.
It should be also noted that skipping one of those very small items makes it impossible to finish the game, as you cannot get back to the location it was on, leading to Guide Dang It. Even worse - it was on the background of almost the same color.
Myst was in many ways a game of pixel hunting—case in point, finding the secret room on Stoneship island. This is actually an accidental case of this trope: the secret room in Stoneship was clearly marked in the Mac version. Due to palette changes when porting the game to the PC, the mark became invisible and finding the secret room was much harder.
The problem of clues hidden in dark shadows is also why the games had a gamma calibration built in to run at first startup.
Riven also had its points of pixel hunting, with switches hidden in tiny decorative buttons on lamp posts looking exactly like every other lamp post you encountered on your way there. Good luck hovering over the whole screen in the hopes of seeing the cursor change.
Sherlock Holmes adventure games tend to fall into this trope, as they try to recreate Holmes' ability to make deductions from tiny clues. In one example, you can't move on until you click a specific footprint to take a closer look, then hold your magnifying glass over just the right spot on just the right clump of grass near the footprint, to find a nearly invisible fish scale.
Circle of Blood, AKA Broken Sword, a game based on legends of the Knights Templar, had so many tiny and impossible to find things in it that it's better known as 'Circle of Mouse'. You (almost literally) had to move the mouse over every pixel in a picture to find something you had to have to continue.
The creative team at Neopetsloves this trope. Their plots (site events) often feature adventure games in which you have to find and click on a very small and almost unnoticeable feature of a picture in order to advance the plot. Here's◊ an example, from this walkthrough. It's not always as bad as it may seem. The tab key in some web browsers allows you to toggle through every clickable object, which usually thwarts any web-based Pixel Hunts. This technique was listed on a fansite as a "secret" for one of Neopets' Mini Games. It can also be used in other places, such as Strong Bad Emails.
Just as well as it displays many, many other common design flaws of adventure games, Limbo of the Lost fails to disappoint in achieving this one too. Have fun looking for flasks and bottles in the shadows, hunting sheets of wool mere footsteps away from normal view, and picking up pieces of wood with one-pixel-tall hot spots! To be fair, if you're making your graphics by taking screenshots of other games, there's a limit to what you can do in the way of object placement.
This trope was avoided beautifully in the Simon the Sorcerer games, in which you could hit F10 at any time and have all the active objects on the screen highlighted for you. The same didn't go for exits from the current location, meaning you could still miss a couple of rooms, but otherwise it completely avoided the need to carefully sweep the screen for tiny items that you would otherwise miss.
This is commonplace in free online games of the "escape the room" variety.
The Lovecraft-inspired PC adventure Shadow of the Comet had an interface that worked by showing a visible line of sight to any item that could be picked up. Problem is, it only worked if you were facing the item in the right way, and was incredibly frustrating if you didn't know what you were looking for, and you usually didn't.
Averted in Death Gate — no item is too small to be noticed, and everything shows a text description when you mouse over it. Still they managed to hide at least one item in plain sight by making absolutely sure that the player sees it, dismisses it as unimportant and forgets about it. When you realize you need these items, you're likely to not even check that room again, and even then you may still overlook it. Finding it was way more satisfying than finding a Pixel Hunt spot.
Shannara, by the same company, has a strange variation: at one point, you end up in a room that is pitch black, and you have to move the mouse pointer around until the text at the bottom of the screen indicates that you're pointing at something that can be used as a light source. (And the room is filled with lots of completely irrelevant junk.)
Old-timey point'n'click game Ween The Prophecy had a couple. At one point you lose three grains of sand in a grass field. You shrink yourself to get a better view, and the end result isn't quite as bad as it sounds because you know you have to look for them in the first place, they're shiny, distinctly off-color with the rest of the screen, and are 3x3 instead of one pixel, and the game is old enough that individual pixels are still pretty big and noticeable.
Later on though, you're thrown in a jail cell and have to Pixel Hunt a nail lodged in the wall. Unlike the previous example, you don't know you have to be looking for it in the first place, it's almost the same color as the rest of the blank wall, it is exactly one pixel, and the first several times you click on it nothing noticeable happens because it's stuck and you have to wiggle it out with several clicks.
Another Code had this occur twice. Once you had to examine a specific window in a cabinet to find a glass with the key to the next room, but there were no clues as to which one to pick. Thankfully, once you found the right, you got a big old close-up for the key you were looking for. Later in the game, you had to pick one book out of a huge bookshelf spanning a wall hiding yet another key and if you hadn't solved the puzzle on the nearby table, you could be at it for a while. Once again, picking the right area gave you a nice close-up on the book you were looking for.
The scene in Sam and Max: The Devil's Playhouse: Episode 5 where you control Maxthulthu in Manhattan is a Pixel Hunt sequence. Your goal is to find buildings that trigger memories, which, with the exception of the Red Herring BoscoTech Lab, are not signposted at all. You are given no indication as to what direction you should be going in. To make matters worse, the city you wonder around in is huge, and the camera angle is pointed upwards, meaning only a few buildings at a time are visible.
An even worse example: In the old LucasArts game (Sam and Max Hit the Road), one of the items you're supposed to get in order to modify a set of binoculars is a magnifying glass, but it's hidden so well in one of the carnival booths that you will easily mistake it for the background.
The Discworld games sometimes had this. Yes, the usable items were captioned, but only once you had the mouse on them, and the Josh-Kirby-lite insanely detailed backgrounds didn't help. Discworld Noir, as in many things, was an improvement ... except when you were locked in jail, and had to find the right brick in a pitch-black room to escape.
Innocent Until Caught has obtainable objects that are literally two (VGA-)pixels small (such as a tiny chewing gum under a table). DreamWeb, however, ups the ante by not only having 3x3 pixel objects, but also cluttering the screen with a zillion pieces of random junk that can all be picked up... Of course, your character Ryan only has so much space in his inventory. Finding the right objects that are actually needed later can be real fun when your apartment looks like a family of bums lived there for a year... Talk about searching the proverbial needle in a haystack. And yes, you can even pick up peas from a leftover TV dinner lying on the carpet. To be fair, in some cases, Ryan utters something like "I think I left something important here" when you want to exit a room.
In the Japanese room escape game Doukoku for the Sega Saturn, if you want to save a particular female character when her leg was caught between an iron grille, in between actions of quite obvious items on screen, you have to click on her hair, where you find a hairpin to unscrew the grille, where you have no hints, the hairpin is also completely invisible in game(you don't even get to see it as an item), and all other similar clicks have actual items drawn on screen for you to see. Not to mention you get the impression that you have to go to other places to find the suitable item, since most room escape games(including this one) requires players to do so. And the girl dies the most horrible death in the game if you leave her(the nice little spoiler hint here is the chainsaw next to her, and you can actually use it to try to set her free, only to find out the the iron grille is just too strong for the chainsaw without putting her into harm).
The Bud Tucker in Double Trouble adventure game presents this problem twice. First, in the park there's a teabag in the floor, and you can't beat the game without it, but it's just 4x4 pixels, and in the middle of scenery. Later on, you need to look for a nail, that is even smaller, and you don't know you can't advance without it. The sad thing is that even after you Guide Dang It and know you need a teabag and a nail, and where they are, they're still very hard to click, and you may need to search for different guides that are more specific on exactly where you're meant to click. There's a third instance in the kitchen with the gorilla, but the area to click isn't that small, it's just that you don't know where do you have to click. You know they overdidit when a guide isn't enough to help you solve it.
Teen Agent requires you to dive into a lake and grab an anchor from its depths. Except the anchor is tiny and barely visible, there are no in-game hints that would suggest its existence, you only get to see it for a couple of seconds at a time (that's how long the character can dive,) and to pick it up you have to click on it right after you begin diving—otheriwse the character will simply ignore your command.
That, and also yet another bookshelf with only one usable book.
Still Life 2 has two chapters of crime scene analysis using a forensic kit. Both of them have at least a couple small target zones that could require any of a half-dozen tools from the kit - wrong tool won't do anything.
True to its name, McPixel takes advantage of its intionally low resolution yet high color depth to make clickable objects nary a single pixels in width and/or height while only a single shade different from its surroundings.
Koudelka (first game in the Shadow Hearts series) is built around a number of what some would call obtuse puzzles. Objects that can be picked up usually give some kind of visual cue such as being shiny or a different color, but other times, they're completely nondescript and look exactly like the pre-rendered background they're placed on. This devolves into the player mashing X constantly to find things that can be picked up to solve the current puzzle, sometimes rooms away with no indication of where to look. Guide Dang It!
Parodied in EarthBound. In the desert, there's a small side-quest involving two lovers separated in the desert. Ness can find them, speak with them, and relay their messages to each other. The catch? The lovers are white and black sesame seeds, and both are only a single pixel big. Your only reward for finding and speaking with them is the satisfaction of knowing they may someday be able to continue their relationship.
In Final Fantasy VIII, there is an interesting case near the end of the first disc, in which you are required to go to an ancient ruin to recover the sword of the previous person to enter the ruin. Problem? The sword is lying on the ground in the first room you enter, and could easily be mistaken for a patch of light.
Disc 2 of Final Fantasy VIII is more or less a continuous series of pixel hunts. And there's also that one Chocobo forest where you need to stand in precisely the right spot if you want to catch the chocobo.
While not necessary for game completion, there is a lot of Pixel Hunt action in Final Fantasy VII. Some of the notice on the boards which you may otherwise just take as background actually contains messages, and in the case of the Turtle's Paradise newsletter, nab you some pretty sweet items. One of the most hidden examples was the back of a signboard in Sector Seven containing a message about Avalanche. If the Ultimania Omega guide is any indication, there is probably a lot more.
In the game Legend of Legaia there is a very well hidden item called the "Platinum Card" which can only be found after reviving the second Genesis tree and then returning to Drake Castle and checking a specific section of a wall.
Many items are found this way. Another example is the "Mettle Goblet", which grants a character infinite AP.
In Super Mario RPG, there are 39 chests distributed all over the world. They are completely invisible. You don't have to find them to beat the game, but it's still a huge Guide Dang It quest.
Shining the Holy Ark has 50 (thankfully optional) Pixies to be found. They're hidden throughout the world and all you have to do is inspect the section of wall they're hiding in. However there is no indication what so ever that a pixie may be hiding in a solid brick wall/pond/pot/statue meaning the only way to find them is to search every single section of wall in the game. Unless you have a guide of course.
The Stardust in The Legend of Dragoon is not only well-hidden, but sometimes requires the player to take some very particular placement just to get Dart to notice it with the X button.
In M.U.L.E., if you go Wampus-hunting, you're searching for two or three blinking pixels. Fortunately, it's an entirely optional way of making a little extra money.
Star Trek: Borg has one annoying sequence where you have to press the button on the bottom of a phaser in order to change its frequency setting; if you fail to do this, a passing Borg would show up and kill both you and your partner. Unfortunately, the hotspot that allow you to push the button is either in the wrong place, approximately two pixels wide or is otherwise programmed to work only 1 out of 256 times. The game's developers did release a patch that fixed one of the game's hotspots... unfortunately, this was the hotspot for punching your partner in the face (a necessary action nonetheless).
Some of the Ace Attorney games use this trope during the investigation scenes. Particularly in the last case of the third game where it's necessary to find a tiny, tiny note slipped almost completely under a chair/cushion/basket thing in order to break a psyche-lock and advance the plot. For the most part, clues in the Ace Attorney series are quite obvious, with only a few hidden. The point of the game isn't to hide the clues, but hide their meanings, after all.
Massively Multiplayer Online Game
An early version of World of Warcraft played this straight. A valuable herb known as Sungrass is a golden color, and, not surprisingly, looks like tall grass. Unfortunately, it's often surrounded by slightly shorter tufts of similarly-colored grass. Blizzard patched that one up in a hurry. Now all herbs (and quest items, and a few other things) give off bright sparkles, turning a full 180 degrees into Notice This.
In Kingdom of Loathing, one (and only one) quest requires you to click the graphics in a choice adventure instead of the buttons. Sure, it's a trope (Bookcase Passage), but unless you use the tab key to select buttons in your browser, you're probably not going to figure it out without spoilers. Also, lampshaded with a literal Pixel Hunt, where you collect pixels from slain Nintendo monsters to make quest items.
There is a hint, though - in Your Dad's Journal, there's a picture of a bookcase with an arrow pointing at one of the books. Now, given the game's never given you a "Pull the book" button in any adventure...
The Katamari series has any number of tiny items that must be collected for 100% Completion. The most annoying ones are low (and thus have to be rolled up exactly), in corners (and thus you have to be the exact right size to get them), or unique (and thus might look exactly like the Non-Unique version - but only appear in one level). Good thing you don't really Need 100%.
The 99 Rooms has some of the most aggravating examples to be found. Special mention has to go to Room 6. You click the switch on the wall. What switch? Um...just click around. Eventually you'll find it. We hope.
The archery game in Wii Sports Resort contains Easter Eggs for you to shoot, granting you an achievement if you get them all. They are very far away to begin with (thus occupying only a few pixels at best), but, even worse, some of them are literally impossible to see from where your Mii stands. It requires paying attention to the arrow cam and other camera idiosyncrasies to learn where they are.
The M.O.A.B. in Call of Duty: Modern Warfare 3 actually can be shot down with a rocket launcher like the Javelin. It is extremely difficult to do so, however, partly because the plane is only a tiny little dot, which appears at the opposite edge of the map of who ever activated it, and partly because you only have a few seconds to shoot it down (if you don't have at least four second on the clock by the time you fire, it still detonates before the rocket can reach it).
Hidden object games can occasionally fall victim to this where objects might be hidden in such a way that you can't really identify what it's suppose to be. Or the descriptor for an object is only loosely similar to the actual object used. Some games even penalize you for clicking too much.
This is the entire premise of "Cate West: The Vanishing Files." You fish around with your DS pointer (or Wiimote) looking for items hidden among a background picture. To add insult to injury, there's quite a lot of foreign objects that you aren't looking for also hidden in the picture and you get penalized for clicking around wildly. There's also a background plot about how the titular protagonist is somehow using her ability to notice details to help police, but the stuff you're hunting for never has anything to do with the case in question.
The 2D Metroid games after Super Metroid have pixel hunting to find hidden tunnels and holes in the ceiling (especially with the ones that can't be detected by shooting or releasing bombs at the wall/ceiling).
Delphine Software loved this one. Near the start of Future Wars, you have to put a flag in a hole on a map which is literally one pixel large, which is fiddly even at the chunky resolution of the time. Another World and Flashback both like putting pixel-high crucial items on the floor.
Super Mario Sunshine has the infamous Blue Coins causing you to have to spray very precise areas in order to obtain 100% completion. Hitting the "Z" button would allow you to see how many blue coins you'd collected in every area. Of course, you would still have to know that there are 30 apiece in the normal courses, 20 in Delfino Square, and 10 in Corona Mountain. And even that doesn't help you figure out which of the area's episodes you should be looking in.
The Kirby series does this ever so occasionally. Nightmare in Dream Land had numerous hidden doors which you had to find to finish the game 100%. One of them was a little red star, no more than 5x5 pixels, which looked like just another star in the outer space backdrop. It helps slightly that the checkerboard pattern of the blocks is missing a block for that spot, and that it moves with the camera.
That this is a remake of Kirby's Adventure doesn't help. The above example was the same, but some of the other secrets were actually changed so they couldn't just be remembered.
Kirby Super Star, in both incarnations, has a hidden planet in the Milky Way Wishes section that can only be found by moving over a specific star in a far off section of the screen, which you can't normally see because the screen pans. The planet's name doesn't show up the first time you select it, either. It's where two of the Copy Essences Deluxe are found and the only way to get 100%, making it a Last Lousy Point.
The home page of the Archie Comics website has such a puzzle, changed often to reflect the season or an upcoming holiday.
Professor Layton and the Curious Village's low point is searching for all of the hidden puzzles. Some of them are very easy to find and hidden on prominent things you'd search anyway... while some of them are hidden in bizarre and arbitrary places (a sliding box puzzle in the open manhole above you? What?). What makes it worse is that beating all the puzzles in the game unlocks the hardest of Layton's Challenges, the Puzzle Master's House. Hint coins are a more minor form of this trope, being optional (unless you suck at puzzles). Luckily, making the robot dog makes this much easier - he sniffs around any place a puzzle or hint coin is hidden.
This trope is the whole point of Hidden Object games, but many still manage to take this to a frustrating, potentially rage-inducing level, because the games themselves are built on the very lazy mistake that these are prevalent in adventure games because people enjoy them.
In Lost in Blue, you have a glossary that has info about various tools/materials/plants/animals/recipes/items as you come across them. The last slot in the plant section of the glossary is a dandelion located in a corner of a certain area of the island that is inaccessible until you get really far along in the game. You have to go hunting for a little weed that is almost indistinguishable from the background. And even though a little box pops up whenever you walk over an item, it's still agonizingly hard to find.
Ace Combat X: Skies of Deception has the mission In Pursuit II, where the way to unlock a custom part for your planes involves destroying certain Special Vehicles. The problem was that thanks to radar jamming that only flickered off every now and then, you mostly had to go hunt them by eyeballing. Even during the lull phases in the jamming, if you were in the wrong place to lock on you would only be able to get a rough idea of where to go. These vehicles were also quite tiny and hard to see, especially given that you couldn't stop and slowly sweep the ground since you were in, y'know, a plane? It also has the mission Joint Operation, where you need to hunt down transport planes with the same radar jamming. So if you weren't in a position to take advantage of the lull in jamming, you had to squint to see the targets and get them before they got away. That's before you even factor in taking down the optional ace.
04: Shattered Skies has the 13th mission "Safe Return" where you need to kill radar-jamming blimps.
One of the activities available in The Sims 3 is finding seeds, which spawn randomly on the ground around the town. The seeds can be pretty hard to spot unless you're deliberately scanning for them or have a close zoom, and of course they're hard to click on. And don't think you can get away with ignoring them - there are a fair number of in-game challenges that require plants grown from special found seeds, so you're going to have to start picking them up sooner or later.
Thank goodness for the Collection Helper lifetime reward. Makes the collectable seeds, bugs, fish and rocks show up on the map and give off a highly visible glow. Plus, its usable by everyone in that household once you've gotten it.
In Animal Crossing, finding some bugs is like this. If you don't pay close attention to some aspects, you won't notice the extremely small ladybug or snail on a flower, and if you get too close they go away. And snails are had to notice because they only appear on rainy days, where the sky is darker and less vivid, making the snail practically invisible.
There's also the walking stick, which has camouflage skills so advanced it fades in and out of reality on trees, unless you see its tiny shadow. And, since the game works with real time, if you miss it you can have to wait MONTHS to get it again.
Don't forget the mosquito. This one makes an obnoxious sound, but is literally so small that when you catch it with your net and your character holds it up in the air, it literally makes a red circle around it to show that your character isn't holding nothing. And if you miss the mosquito and it bites you, it goes away, making you have to search more.
Animal Crossing really has a ton of these. There's also fleas, which are indicated by tiny dots occasionally coming from your neighbors' heads. Though their Verbal Tic will change if you talk to them into saying things like "itchy" and "bzt" if you talk to them.
The Virtual Villagers series of casual games is very prone to this trope. The player has to pick up a sprite and drop it on a hotspot to get a particular reaction, such as starting a villager working on a task. This is even harder than clicking on the hotspot since when clicking the cursor gives a more accurate indication of screen position. The hotspots in the ports to iOS Games and Android Games are possibly even more difficult to find than in games played on desktop or laptop computers because of the smaller touch screens.
Theresia: Dear Emile demonstrates how to make this trope even worse. It's a rather low-budget game, and gameplay outside of cutscenes is represented as a series of 2-D sketches. Usually there isn't a "before and after" for picking up an item—the item simply doesn't appear on-screen, and you have to use the "look" command on every single object to tell whether, say, there's a key stuck in the middle of those chain links. To make matters worse, there's no visual distinction between items that can be "looked" at and background items that give a generic "there's nothing here" message.
The SP items in Resident Evil Outbreak are hidden in the scenery this way with no visual indicator. Finding them is a real chore, especially since what items are loaded up can change between instances.
Silent Hill 1 doesn't have the "protagonist's head turns to look at interesting stuff" mechanic of the later games, and the items are as low-poly as the whole scenery. Health items and ammo boxes are quite distinctive color-wise, but key items (like keys themselves) are usually a small nondescript mass of pixels you will most likely glaze over.
morphE is a comic designed to play like a visual novel and has "Investigation Mode" updates where in order to move to the next update you must find the object that the characters are looking for in the comic. Other items can be viewed for quick conversations.
In Baldur's Gate, every outdoors map had some form of treasure hidden somewhere in it within an area only a few pixels across. There was never any indication that they were there, you had to find them by chance. None of the items were ever plot relevant though, only valuable bits of loot.
One of these contains a Ring of Wizardry, possibly the most powerful item in the game. The size of the hidden area is exactly one pixel. Good luck finding it without a Guide Dang It moment.
Baldur's Gate 2, thank God, averted this trope by allowing you to hold down alt to light up all such tiny treasure chests in impossible-to-miss luminous turquoise.
The new Enhanced Edition also has the highlight feature, as does running the original game in the Baldurs Gate 2 engine using BG Tutu.
Planescape: Torment, which also used the same engine, did this, too, but outlined clickable objects if your mouse strayed over them.
The early Warhammer video game Shadow of the Horned Rat featured magic items lying around some of the battle maps that you could pick up and use. The problem? These items were represented by a single pixel that occasionally turned white. Pretty much the only way to discover them was by chance (and some of them were hidden well out of the way), and once a unit had picked one up, it was stuck with it, thus usually rendering the item useless anyway. Frustrating? Oh my yes.
The released-without-being-finished add-on to Ultima VII Part II: Serpent's Isle,The Silver Seed, had the most powerful item in the game — a ring that made spell components unnecessary — hidden on a dead monster that can barely be seen under an avalanche in a section of the dungeon that seemed to go nowhere. Even knowing the area to look in, it's hard to find find it until you look at a screenshot.
Ultima VII had a few pixel hunts as well, in particular a very well hidden switch in a dungeon and the key to the shack holding the Hoe of Destruction. It's inside a dead fish in an area covered with identical-looking dead fishes. And the right one is hidden under some debris that you need to move out of the way first.
For the most part, significant objects in Morrowind are easy to find. However, one of the early Fighters' Guild quests has you looking for a Dwemer Cube in a nearby ruin, and you aren't told what it looks like. It's a three-inch cube in muted colors, sitting on a shelf in an easily-overlooked alcove of a very large room.
A short sidequest has you searching for a ring at the bottom of a pond. In good light conditions it borders on one of these, but to get the full experience you need to happen upon it at night. Having a character that needs to periodically surface for air is a bonus.
In Oblivion, the useful enchanted helmet Fin Gleam is on the seabed off the coast of Anvil. Even if you know where to look, actually finding it can be a challenge in itself.
You wouldn't think something the size of a sword could be the object of a Pixel Hunt, but you'd be wrong. In The Elder Scrolls V: Skyrim, some enemies have the ability to disarm your character and send their weapon flying in a random direction. Depending on the angle of the attack and the geometry of the room, it might be right by your feet where you'd expect it, off in some dimly-lit corner obscured by a pile of Vendor Trash, or it might have clipped through a floor or wall and be irretrievable. Many players choose to Save Scum when facing these enemies rather than futz with it.
Absolutely every single object in Summoner that can be picked up is in the form of a generic brown sack about the size of a football, and is always on traversable ground. Now, imagine that you have to stumble on some objects in order to get critical quest items, often in generic-looking random encounters, in some of the biggest maps in an RPG. That, and you have to be practically on top of the bag before its graphics work. It doesn't matter how eagle-eyed you are, you can't see what it won't show you.
The developers of Age of Pirates 2: City of Abandoned Ships had the bright idea to make this this an actual quest where you go into the jungle and look for a marble-sized gem in the grass. Or a tiny brown key somewhere on the brown decks of a dozen ships.
The absolute best item in Planescape: Torment is found in a warehouse before you fight Trias, in a pixel on the top left of the room. It's literally finding a needle in a haystack.
In Diablo, you could hear the sound of a ring drop from a monster, and spend the next 10 minutes carefully searching the ground around you.
Thankfully, in the sequel you can hold Alt-key to show all items on the ground.
And Hellfire added the Search skill/spell. Also, since you could pick up something as soon as the cursor was in the same square, you had to search much less than you'd think at first.
NetHack, sort of. Instead of Pixel Hunt, there's Vibrating Square Hunt. In order to get to the final dungeon below Gehennom, you need to find and stand on a certain square on the bottom level. This wouldn't be so annoying as it is, however, the level (and around the twenty previous levels before that) is a randomly-generated maze.
UnNetHack made this a bit easier by informing the player when they were a few spaces away, rather than having to step directly on it.
The SNES version of Shadowrun had a limited palette, small sprites, and muted colors to boot. On the bright side, your cursor would "stick" to items when you moved over them. On the incredibly frustrating side, you controlled the cursor with the gamepad, which meant a slow, fixed scrolling speed in the rare case where you had to perform searching-by-frantic-cursor-hunting.
The three Mass Effect games have this in different degrees while exploring on the Normandy the different solar systems:
Mass Effect 1: For finding resources or Prothean disks or Asari writings you would sometimes need to move the cursor all over asteroid fields hoping to hear the *ping* of an object, although sometimes an object of interest would also glint briefly on your display.
Mass Effect 2: Some moons and dwarf planets are considerably obscured or hard to see, to detect them you would need to come close to them and hear the distinct *ping* of them but since they can be much smaller than your ship model, your only clue of their existence would be the percent explored display.
Mass Effect 3: The third game incorporates a scanner which can detect pixel-width objects of interest in a solar system, the caveat is that using it too much will attract the Reapers, so its very common for players to bombard whole area of a solar system quickly and then get the hell out of there.
Wide Open Sandbox Game
Grand Theft Auto: San Andreas has this too, surprisingly, on it's map screen for turf wars. One of the turfs is a single sidewalk in the north edge of the map. On the in-game map this becomes a barely visible line, usually yellow against the green of your gang.