Q Billion , released on 1989-12-22 for the GameBoy, is a puzzle game where you control a mouse that must level out a playfield filled with stacks of tiles. Your goal is to climb onto one stack and push a taller, neighbouring stack so that tiles fall off, until there are no tiles stacked on top of each other. The challenge lies in navigating the mouse through the playfield without being blocked by the stacks. The mouse can only move a single tile at a time, requiring you to juggle moves carefully to progress. This simple yet addictive gameplay mechanic is reminiscent of classic Japanese puzzles like Sokoban .
As you progress through the game, new tiles are introduced, including hearts, squares, and stars. These special tiles can be eliminated when moved together in groups of four or by clearing the uppermost layer.
The game also features a time attack mode where you must solve ready-made puzzles within a limited amount of time, as well as an editing mode that allows you to create your own levels.