In a video game, Ratchet Scrolling occurs when the game screen only scrolls in only one direction and prevents the player from backtracking.
This is similar to an Auto-Scrolling Level, except that the scrolling does not occur by itself, but in response to the player's movement through the level. Like the nature of a mechanical ratchet, it scrolls forward freely as the player moves, but 'locks' in place and prevents the player from backtracking.
Lesser versions may allow the player some degree of backtracking, but only to a certain distance or recent checkpoints.
Easily becomes a form of Fake Difficulty, especially when the screen is ratcheted vertically, where any platforms that disappear even a few pixels off the screen edge may leave Bottomless Pits in their wake, in defiance of all logic.
In early video games, Ratchet Scrolling was a way to improve performance. If the player could only scroll in one direction, game objects and enemies could be created when they enter the screen and erased as soon as they scroll out, reducing memory usage. A Forgotten Trope now, but was once common, particularly in Platform Games.
- Almost all Beat-em-Ups and Action Games with platforming elements in the arcade will do this to you.
- The original Super Mario Bros., the Lost Levels Mission Pack Sequel, and Super Mario Land. The way the levels were compressed required this.
- New Super Mario Bros. has "Challenge Mode". On side-scrolling levels it enables this, on vertical-scrolling levels it becomes an Ice Climber-style Rise to the Challenge.
- The Deluxe port of the original game lets you backtrack to a certain extent, because the game is pixel-for-pixel and the Game Boy screen is smaller than the NES output screen.
- Syobon Action abuses it to torment the player.
- Ninja Commando is a Shoot'Em Up that does this.
- Battletoads for the Game Boy, NES, etc. However, some levels were free-scrolling.
- Ren & Stimpy: Space Cadet Adventures
- The original Glider had this.
- All Nintendo-era Contra games featured both varieties of this. Not funny when in a vertical shaft, and you fell off the platforms...
- Shoot 'em up Construction Kit.
- A LittleBigPlanet level entitled "When things don't go right, go left" is effectively a basic platformer, apart from the fact you scrolled left.
- Pretty much all Action 52 side scrollers. Can get you stuck in an Unwinnable situation, as in Dam Busters and Non Human.
- The Kaizo Mario inspired level of Pickory will only scroll to the right, but you can backtrack up to half a screen. One trap can only be avoided by exploiting the scrolling and the fact that anything that goes off the left side of the screen is destroyed.
- Adventure Island I and III feature this. II has arbitrary points after which the screen couldn't scroll backwards anymore, but otherwise scrolling is two-directional. III has two-directional vertical scrolling and the only time there was two-directional horizontal scrolling was in stage 2-6.
- Kid Icarus is notorious for its vertical ratchet scrolling - if you fall (and don't have a feather) you die instantly and have to repeat the level. Even if there was a platform just off the screen. Your little wings are no good for flying.
- Played With in Bunny Must Die. You start out unable to move to the right at all, but the first available power-up gives you this ability. It's still possible to clear the game without it, though.
- Layla for the NES, which can lead to some Unwinnable situations.
- Kid Kool, obviously modeled on the example of Super Mario Bros., disallowed going backwards. Its Spiritual Successor Psycho Fox followed suit.
- Kick Master doesn't let you go backward; while it's a largely linear game, there are many hidden items that can be missed.