1) Exact targeting - targeting reticle needs to be roughly/exactly over a target to hit anyone, it's not sufficient to form a line of fire with reticle and the source that intersects the target. Not for first person perspective.
... examples: Showdown Effect
2) Every nth subsequent attack is Special.
... examples: Hexen (warrior hits harder every third attack), Rayman Origins (Rayman hits harder every ~third attack), Kingdoms of Amalur: Recoking (every 3rd/4th attack depending on weapon)
= progressive attacks
3) Convoluted paths - player is shown their goal destination nearby, but is required to follow a convoluted path to get there. Such as they want to get to the other side of a door, but the door is locked, jammed, blocked, or so.
3a) Player arrives on the other side of the door and trivially opens the door even though there's no need for it.
3b) Same task but player finds a key and backtracks to the door (perhaps a bit too common to tag?)
... both only if they happen repeatedly or contribute a significant amount of game time.
... examples: Half-Life 1 (offices level notably)
4) Projectile weapons become effective or more powerful after the projectile has traveled certain distance. For example a warhead is armed only half-a-second after being launched, so it won't explode if it hits something before that. Or a projectile splits traveling 10 meters or so, effectively multiplying the damage (even if it makes no sense). MIRV is fairly well known non-game example.
4a) Arming time (fuze) - the projectile simply won't do its main job if it hits something too soon.
4b) Splitting projectile - after traveling far enough, the projectile splits apart.
4c) Accumulating projectile - the longer it travels, the more powerful it gets. Either literally the single projectile becoming more powerful, or it spawns a new projectile or other form of attack at steady intervals.
... examples: Guns of Icarus Online ("Lumberjack" has arming time), EDF Insect Armageddon (some projectiles split after flying far enough, and accumulating projectiles in terms of spawning new ones at steady intervals), Scorched Earth (MIRV and various others), League of Legends (accumulating projectiles), Dota 2 (another with accumulating projectile)
5) Player encounters allies half-way through an enemy/trap infested location, such as a dungeon. For some reason those allies had somehow reached the location without defeating anyone or disarming said traps. Especially if nothing about them suggests them capable of avoiding doing so (e.g. an army company or some bumbling village folk).
... examples: Baldur's Gate 2, TV Tropes article
6) Player can see deep into solid matter. Kinda implied by lack of line of sight, but it's not required part of it. You can have the stuff obscured even without line of sight.
... examples: Terraria (though with it the darkness kinda counteracts it, but you can light the areas more to see farther into solid matter), Dig Dug, Boulderdash, etc.
7) Intuitively expected weak points do not work.
... examples: undead (zombies, skeletons, etc.) in some games do not care if their head is removed/destroyed
8) As variant of above, composite opponents that have parts that serve no purpose and thus removing them does not help the player.
... examplles: none that isn't covered by #7?
9) Limited dismembering/crippling. As in, only works against certain enemy types and/or only with certain body parts.
... examples: few games have removing/crippling legs from enemies that causes them to drag their bodies around with arms instead, Warframe, Colonial Marines, some of the Aliens vs Predator games, etc.
10) Inciting strife among NPCs, such as causing infighting. Whether this is by framing someone or some other method. Excluding causing them to shoot each other by abusing poor AI via maneuvering or similar (e.g. as seen in Doom).
... examples: Bully (framing/false evidence), Prototype (disguising as a commander and ordering your enemies to attack one of their own)
11) Randomized weak points.
... examples: Resident Evil 4(? one of the mobs had boils that were randomized and they died only from them), Warframe (some bosses have randomized weak spot location)
12) No separate levels.
... examples: some (not all mind) open world or sandbox games, Really Big Sky is a shmup with no levels (the game continues forever, generating the level/challenges as it progresses), some endless running games, etc.
13) Player provided texture packs or similar. Player can trivially alter game appearance.
... examples: Minecraft, various roguelikes with tilesets, Cubemen 2, etc.
14) Work sites need workers
... examples: Settlers(?), Black & White series, X-COM and games inspired by it, and some others
= workers
15) Manually strung traps. Any traps player needs to interact with for them to do anything, such as pulling a lever, cutting a rope, pressing a button, or such. Not including explosives in most cases (explosive objects, remote detonators).
... examples: Sang-Froid (net traps need to be shot to work),
16) Filter triggers. Any trigger mechanisms that react to only certain things (objects, beings, whatever).
... examples: there's several puzzle games with this, though I remember none specifically
17) Framerate lock (besides VSync or optional frame rate limiters). Seen in console games being locked to 30 FPS despite NTSC refresh rate being 60 and modern displays not being tied to PAL/NTSC and thus being able to go up to 120 Hz depending on the device.
... examples: several upcoming console games have been announced to be locked to 30 FPS
18) Some structures are automatically built.
18a) These are just padding and serve no actual purpose, generally just make it seem like some place is flourishing more.
... examples: Majesty series (housing and other features are built but has no purpose, sewers being auto built are actually purely detrimental)
18b) These are actually same things you could build as well or are otherwise beneficial or impactful.
... examples: Victoria II (industrialists build factories for example within your nation)
19) Convenient mission/level end. No matter what's going on, when level/mission objective is reached, the mission/level ends, no matter what it was or where it was. So even if the mission was to destroy/kill some target deep in enemy territory and you have enemies swarming around you, the moment you complete the objective, the level/mission ends, no fighting to escape or anything.
... examples: (unfortunately I remember none, but I know these exist, especially in older games before the subsequent escape became more commonly included. will try to look for them)
20) Past comes to haunt the protagonist. Whatever they did long before the game started has decided to come pester them. As besides amnesia or background fluff. Past dues being collected, in essence.
... examples: Mars: War Logs
21) Apparently good choices and deeds actually lead to "worse" results than the less good (even evil) choices or deeds.
... examples: Dragon Age: Origins, Witcher, Knights of the Old Republic 2, ...
22) Companions automatically search and collect for items in the environment. Not when they simply point that they're there.
... examples: Bioshock Infinite, Dragon's Dogma
23) Areas are populated differently after player goes through them. Such as a road patrol post might be set up in some area they go through of and the number of enemies found in the area on subsequent visits is greatly reduced while there's an added friendly presence.
... examples: Dragon's Dogma (only few areas get drastic change in population, there's few that get smaller population and others with just the harder enemies removed)
24) Boss battles are not constrained into an arena, allowing player to flee them as they see fit. Or generally allowing player to flee from boss battles without causing a game over or the quest needing to be completely redone to get it.
... examples: Dragon's Dogma
25) Dynamic (sub-)quests/tasks/objectives created according to the situation or simply to create stuff to do on the go. A variant of task generator in essence, but these are pushed to the player on the go instead of requiring them to look at a job board or find "random" events in world map or such.
... examples: Section 8 (+ Prejudice), PlanetSide 2 (alerts?)
26) Lossless class switching.
... examples: Dragon's Dogma (with odd variation where you can keep passive traits gained from classes but actives are inaccessible unless the other class has them too), pretty sure this has been in other games as well but fairly rare
= known fairly well as Job system
27) Leading by hand. Player can grab someone and pull them along, leading them somewhere. Variant of auto-follow but initiated by the person going to places rather than the one following.
... examples: Ico (basic gameplay element getting your damsel in distress to places), Space Station 13 (helpful feature for getting people to places as well as something for law enforcers to use for leading miscreants to prison)
28) Dependence on game manual to understand how the game works. Usually seen with important things unexplained in-game, such as character attributes (especially if if they have esoteric names) the player modifies with each level up that don't show any direct results (other stats don't show it).
... examples: many old games, such as Anvil of Dawn, and newer games possibly intentionally cryptic, such as Demon's Souls, etc
29) Dependence on intuition to understand how game works. Same as above, but they aren't explained in the manual either.
... related concepts: hidden attributes, hidden item stats - except they aren't hidden, they're just unexplained or not directly understandable (e.g. a weapon might have lethality, force, and weight attributes and they don't match the damage numbers or other things you see much at all but actually do, and you might learn how they work after experimenting with many).
... examples: n/a
30) Bizarre dangers, such as a boulder rolling back and forth in a corridor, intermittent spells flying around without clear source (especially if clearly distinguishable as alike the ones player or other characters throw around).
... examples: Anvil of Dawn and many other old games
31) Boy/girl and their monster friend.
... examples: The Last Guardian, Majin and the Forsaken Kingdom, Drakan (maybe?), Papo & Yo, etc.
... possibly related to A Boy And His X
= monster friend
32) Abstract/surreal/bizarre levels. There's already bizarre architecture, but I feel there needs to be something else for things like what old platformers had. Platforms that move for no apparent reason, platforms that hang in the air with nothing supporting them, and other such things. Inclined to use `surreal locales´ or similar, to distinguish from overall surrealness.
... examples: any old platformers or retro platformers
33) Characters "choose" bizarre routes. Similar to above and other surreal/bizarre tags, but instead of the levels being surreal, the characters choose to follow routes that make them such. For example, in Trine (2?) the characters are climbing onto second floor of a witch's house by jumping on the bubbles rising from some kettles, instead of looking for and going through stairs or similar. This however easily goes into bizarre architecture land if there is sufficient evidence that there are no stairs or similar to reach the locations from. Sort of like surreal parkour, where the characters choose the most "direct" path no matter how ludicrous (or slow) it is just because it's the most direct.
... examples: Trine (1 & 2)
34) Spikes.
... examples: platformers, TVTropes
= deadly decor
35) Controlling a lineage. Player controls character A, A has a child B, A dies and player turns to control B, B similarly has a child and later dies, control passes again to the child.
... examples: Crusader Kings 2 via ruler succession (not always tied to offspring, AFAIK), Faery Tale Online (quite literal instance), Rogue Legacy (not really, this is mostly just explanation for where the new characters come from)
36) Once per mission, level, day, etc. abilities, devices, or such.
... examples: Battle for Graxia (fifth ability can be used only once per match), Survivor Squad (gadgets can be used only once per mission), and some RPGs have once per day abilities
37) Players ability to read or write is interfered with.
... examples: Rogue Legacy (dyslexia character trait), ZombieMud (various spells can do this for anything you say), original Rogue/Nethack maybe?
38) Players can steal from other players.
... examples: Mighty Quest For Epic Loot, a lot of browser based strategy games, a lot of freemium strategy games on mobile devices
39) Player character/vehicle can get so damaged/hurt that they can not continue but the game itself continues or otherwise loses some integral ability to continue. For example, if dismemberment is in, player character loses both arms but the game continues until they're properly defeated. Player runs out of ammo in a match where no ammo replenishment exists. And so forth.
... examples: World of Tanks (although ramming is still possible after you've lost all your ammo as well as meatwalling for your team mates, you're largely useless at this stage, especially if you're last one alive on your team), many Mechwarrior games have this by losing all ammo or the actual weapons (some mechwarrior games have ammo replenishment and repairing mid-mission tho), Die by the Sword (player can lose a leg and both arms and the game will continue on)
40) Party members or similar are nowhere to be seen until needed for cutscenes, dialogs, or combat.
.. examples: many old top-down RPGs, Zeno Clash 2, and others.
41) Fake features. Game has features that were intentionally added but do nothing or are misleading.
... examples: Rise of the Triad 2013 (weapon reloading [guns that you can do this with never run out of ammo from their clip anyway regardless of reloading] and ironsights [accuracy is not increased unlike in contemporary games that have it])
42) Protagonist is part of a group that goes on a mission, but you only control one character ever and never see the others (and never are swapped to them).
... examples: Rise of the Triad, Hexen, Hexen 2, and various others where player has choice of multiple characters (cutscenes usually have all of them; especially games with no cooperative multiplayer).
43) Sparse/semi-solid barriers behaving contrary to reality or much closer than expected. For example, windows being unbreakable (when one would not expect them to be armored glass), iron mesh fences behaving like iron walls, etc.
Iron meshes have actually 3 variations on how they work in games: iron walls, movement barriers that don't block attacks of any kind, and proper meshes where you can hit the individual metal bits but can shoot through the various openings.
Can be generalized into quasi-solid barriers, which also leads to a variant of barriers that can be moved through but not attacked through.
... examples: first person shooters mostly
44) Jump height is dependant how long you press the jump button. Probably should be prioritized for games where you actually benefit from below max height jumps.
... examples: numerous platformers mainly
45) Enemies can benefit from same power-ups as player.
... examples: in Unepic enemies can be healed by health drops
46) Enemies can pick up same objects as player and use them as weapons.
... examples: ?
47) Enemies can pick up things player can't and use them (as weapons).
... examples: in Batman: Arkham City enemies can pickup firearms and various objects as improvised weapons
48) Each player experiences different things simultaneously in same place. For example, one player character hallucinates something else happening than another sees and experiences.
... examples: Dead Space 3 coop
