Cosmos Bit is an action-adventure game inspired by the 1987 title Metroid. Players control space warrior Stella Mironova, navigating levels filled with monsters, traps, and environmental puzzles. The game utilizes a retro pixel art style and an Amstrad CPC color palette.

Gameplay involves collecting minerals to develop skills and unlock new abilities, enhancing Stella's combat and exploration capabilities. Cosmos Bit features four bosses, a variety of monsters, and high-difficulty challenges designed to be demanding but not frustrating. The game includes achievements for players to pursue.