Mosa Lina is an abstract Puzzle Platformer described as "a hostile take on the Immersive Sim".
Each time the game is played, the player is dropped into a level (randomly selected from a number of presets) consisting of floating blocks, vines, and various hazards. Their goal is to touch (or get rid of) all the fruits in the level in order to unlock the exit portal to complete the level. Each level the player is randomly given 3 abilities from a set of 24, which range from summoning platforms, to manipulating gravity, to shooting fish.
The presentation is extremly abstract, without anything resembling a story to speak of. The game relies heavily on Emergent Gameplay, where no solutions are intended, and it's the player's job to figure one out with their current tools (if it's even possible).
Originally released on October 17, 2023, the game has received a few updates since then, adding new tools, random level effects, and a backflip.
The game provides examples of the following tropes:
- Abnormal Ammo: The items you're capable of shooting from your gun range from arrows, to fish, to the gun itself.
- Emergent Gameplay: The crux of the gameplay, with the Steam store page describing it as a game "where nothing is planned, and everything works."
- Endless Game: Completing all nine levels in the standard mode sends you to a strange area where Death Is the Only Option, segueing immediately into another set of levels. The Raw Random mode emphasizes this more, with an endless stream of random levels and random tools.
- Escort Mission: One random effect has a turtle that must be protected or else the end portal disappears. Downplayed in that the turtle can die from hazard damage with no repercussions, but it's not allowed to go offscreen.
- Head Swap: The head of the player character is replaced by the icon for whatever tool is currently selected.
- Hitbox Dissonance: The icon on the head of the character doesn't contribute to the hitbox, so it's possible to squeeze under some spikes that look like they might hurt you.
- Level Goal: The end portal, which must be reached after all fruits are collected.
- No Plot? No Problem!: There isn't even the barest mention of a plot.
- Random Event: A number of random effects can occur on the levels, including dropping a spike ball on it, giving fixed elements gravity, freezing moving elements in place, and so on.
- Springy Spores: The Bouncer tool takes the form of a traditional red capped toadstool.
- Training Stage: The game always opens in a small, walled in room that explains the controls and lets the player get a feel for the basic gameplay, as well as a few of the items.
- Wrap Around: The Phaser will pop out from the other side shortly after going offscreen.
