Depth Perplexion

The tower is blocking him.

There's even enemies that you can barely see, like this tiny mouse on the fence in the background. (The tiny mouse somehow hits Dorothy) Like are you kidding me? That doesn't even make sense from a perspective view-point. She's like standing in front of the fence.

—The Angry Video Game Nerd on The Wizard of Oz for SNES

Before the days of 3D graphics, gamers were only concerned with three layers: the background, the foreground, and the "main layer" in between that the player actually resided on. This is the only layer that is supposed to matter. Sometimes the foreground might block your view, and some guys may attack from the background, but that's it.

When this trope is in effect, you can throw all the rules of background vs. foreground out the window. Those Goddamn Bats clearly flying in front of bricks that block you will still kill you with Collision Damage if you get near them.^[1] See that thunderstorm in the distant background? It'll kill you if you're in front of it when lightning strikes. If you're lucky, you can shoot through walls too.

The most common instance of this is enemies and bullets (their bullets) that go through walls by overlapping them. Most gamers just take this for granted, as it has been happening since Super Mario Bros. with Bullet Bills, if not earlier than that.

This is like Depth Deception except with any semblance of logic removed. The enemy or object in question isn't actually especially big or small... it just somehow affects you despite the fact that it logically shouldn't be anywhere near you. It's most common in Isometric and Side Views, and optical illusions such as the Penrose staircase make it Older Than the NES.

Examples of Depth Perplexion include:

• As quoted, The Wizard of Oz for the SNES features some incredible examples. Aside from the mouse, there are grandfather clocks you can go in front of... but the hands on them hurt you.
• Mega Man is an early example of a game where your bullets go through walls.
  • The series and its spin-offs sometimes flip-flop about it. In Mega Man and Bass, Bass can't shoot past walls with his buster unless you equip a certain item. Mega Man X 5 and X6 made most basic projectiles unable to pass walls, yet in X5 X's charged shot with the Falcon Armor can pierce both enemies and solid walls. One game later, the armor gets broken and Alia barely fixes it, so among other things the charged shot looks exactly the same but can't penetrate anything.
• In Castlevania Dawn of Sorrow, the Final Boss (Menace) can hit you (for a lot of damage) with a foot that is clearly in the background behind Soma. It even is of a darker shade to emphasize that is indeed in the background.
  • Even worse, there are very many enemies in the game (various forms of Barbariccia, the Valkyries, Demons, the various Mini-Demons, and Gaibon come to mind, most of whom fly, whose attacks and AI can lead them off-screen, where they can easily prepare or launch attacks that you can't even see. Of course they are out of range of most of your weapons and Bullet Souls. Gaibon, for example, breaths fire diagonally downward, and you fight them in tall shafts. Sometimes as many as three at a time. All hiding off-screen, torching you when you try to climb up to them.
• The Famicom Transformers game has solid bricks that the player can't shoot or pass through. Enemies fly in front of the bricks, but they still kill you with Collision Damage if they touch you.
• Super Mario Bros 3 where you could hide behind the background of certain levels. This is wholly intentional, however.
• Space shooters in general are likely to allow enemies and their bullets to fly in front of walls in your way, and yet they still affect your layer. Sometimes walls are electric or made of Hard Light that enemies can pass through to avert this. Additionally, since the player's ship's hitbox is usually very small, bullets will appear to pass over it without colliding... unless the bullet hits the very center of the ship.
  • Danmaku shooters are the worst, as not only will bullets fly in front of obstacles if present, but also in front of your character, unless they collide with a hitbox. The only way this would work is if the hitbox is actually closer to the player than the rest of the character—which makes sense if it's a cockpit in a vertically-scrolling shooter, but significantly less so if it's part of a person or a cockpit in a side-scrolling shooter.
  • In a surprising version of this, in Ikaruga, not only do enemy bullets not do this, but in the second stage, the player's ship can act as part of the background to avoid certain obstacles. This is because if the ship is lined up perfectly with the one-pixel gap between obstacles, the ship itself will appear to fly under them unharmed.
• I Wanna Be the Guy has both Depth Deception and this.
• In StarCraft, it's possible to shoot between high ground and low ground even if the ground should be in the way. It's also possible to shoot from low ground to low ground when there's a wall in the way.
  • Warcraft II had submarines which could only hit other ships; they could hit over land. This is a limitation of the pathing code of both games, although it's made up by the fact that a unit that shoots another makes itself visible(and thus shootable) even if you wouldn't see it normally.
• Wayne's World for the SNES has a level with poles that are clearly in the foreground, but still block players walking on the sidewalk.
• Equinox is an early 2D game that simulates a 3D isometric environment. There is a minor Depth Perplexion glitch that can occur in the game due to the graphic layering that performs the simulation. Read here for a good explanation.
• Indiana Jones and the Temple of Doom for the NES is just... wow. It's simultaneously an isometric 3D view and overhead view. See it for yourself around the 6:30 mark here.
• La-Mulana's most common enemy is a bat (in two sub-types) that flies "in front of" the walls. And it's definitely of the Goddamned kind.
  • And because they are of the same color, they seem to fly BEHIND water and other objects that are behind your character.
• The Glider games had balloons, copters and darts that could fly in front of furniture (deadly to crash into) but caused Collision Damage all the same. The games never had a strong sense of layering (it mostly affected graphics); it's remarkable that the thunderstorms in Glider 4.0 don't kill you.
• Little Red Hood is supposedly in a 3/4 overhead view, but if you jump in front of a tree, your head bumps into the trunk. Another AVGN explanation is at the 11 minute mark here.
• The NES game based on Robin Hood: Prince of Thieves was insane with this, as shown in the picture at the top: Much like the Little Red Hood example above, the game played out in an isometric perspective, which factored into the collision detection, forcing players to swerve around towers so as not to walk straight into their peaks on ground level.
  • Also seen in Super C.
• Pretty much the same problem was present in the overworld of Mickey's Racing Adventure for the Game Boy. The Treehouse Glade in particular is made rather maze-like by your inexplicable inability to walk behind trees.
• In the first Sonic the Hedgehog, Batbrains can fly through walls in the Marble Zone.
• Freeware game Action Fist has this issue in the game's second zone, a driving level. Jumping and moving up the screen have nearly the exact same result, except the former makes you come back down. Only averted with the boss, whose lightning attack can be jumped over.
• The Legend of Zelda CDI Games had numerous problems with that. For an example, a top part of one of the pillars blocks the player but the bottom part doesn't. Many screens use painted landscapes that have a lot of depth, but the gameplay is strictly 2D like at 6:40 here.
  • While we're on the subject, this trope also affects at least one main series game: The Legend of Zelda Links Awakening. The game uses isometric perspective but lacks Z-levels, so it's possible to, say, hit an enemy on the ground while swinging the sword at the crest of a jump because Link and the enemy are at the same height on the screen, even though perspective implies that the enemy is below and to the side of Link. This was fixed in The Legend of Zelda Oracle Games, which use the same engine.
• In Trilby: The Art of Theft, guards tend to pass right under your sprite. The catch is you're hugging the wall farthest from the screen, meaning they should be layered on top.
• In the Nintendo Wars franchise, planes can fly over any space, but can't pass through spaces occupied by other units. Even ground units. Even naval units. Even submerged submarines.
  • The same happens in Super Robot Wars games.
• The first Wizards and Warriors game had floating tree stumps in the forest level.
• The otherwise excellent Golden Sun suffers from this, in that sometimes, due to the overhead view, it's difficult to tell if a pillar is standing upright or lying down. It can also be tricky to gauge distance between platforms, resulting in several minutes of random wanderings until you accidentally stumble across the solution. Thankfully, it only happens occasionally.
• The "shoot through walls" variety is Justified in the Metroid series, where Samus can only shoot through walls if she has the Wave Beam, which explicitly has the ability to penetrate solid matter.
• Rygar had this issue in the overhead areas. If you jump, your Diskarmor would register a hit on whatever was in the same place on the screen, even though your hero's shadow was about six tiles below. Savvy players could use this trick to easily defeat one of the bosses.
• Super Mario Bros. 2 US has Pokeys that go right through cacti, even though the cacti block you. And you can stand on top of the Pokeys, as well, "riding" them past the normal cacti.^[2]
• In Terraria, Fire Imps can throw fireballs in front of blocks, but most of your projectiles get blocked by them.
• This is apparently an issue with making 3DS versions of older games. Each sprite has their depth coded into the 3D version, which works great, until, uh-oh, enemy X existed on two planes at once in the original game. Another issue is bullets in an overhead perspective that make their way from a ground shooter to the player in the air; on a flat screen, the player just assumes the bullet was increasing in height as it reached the player, but of course, that was never programmed in; the bullet hits the player as long as the two overlap, with no regard to height.
• In the original Pokémon Red and Blue games, the player character could only move over objects or be blocked by them; thus, you could not, say, walk behind a skyscraper, even a road could pass behind it, because it's blocked by your game perspective. This was changed in Pokémon Ruby and Sapphire where you could walk behind lampposts.
• In the C64 version of Rambo, the tops of palm trees would block your path and had to be blown to smithereens with explosive weapons if you were to pass. All the while non-explosive projectiles from your and your enemies' weapons freely travel through everything.
• This trope is the whole point of Echochrome, where your player character (a little wooden artist's mannequin) can travel across a gap if you couldn't see it.
• You can't walk behind flowers in pot in a table in Final Fantasy IV.
• Some of the beams in the New York level of Samurai Zombie Nation come from the buildings in the background, but they damage you just the same as the ones in the foreground.
• In the online Warrior Cats Hunting Game, enemies can travel through tree stumps that you can't get past without jumping over them.
• A curious non-videogame example: in Dr. Slump an one-time character was a wandering samurai who casually punched a mountain in the background right behind him... and smashed it.
• In FHBG, Spinner, Burger, and the collectable chips fly in front of the walls.
• Downplayed in RHDE. Pieces of "tall" furniture (bed, fridge, toilet, etc.) can't be placed overlapping the north side of a room. But units can still walk behind them once placed, and the game displays this by exploiting a quirk in the NES PPU's sprite priority. On the other hand, missiles can go over your own walls but stop at the opponent's walls.

1. ↑ if they're Goddamned Bats, and you're not a One-Hit-Point Wonder, then they're probably positioned just right to drive you into something that will kill you instantly
2. ↑ MOVE FASTER POKEY!