Monolith is a roguelike twin-stick shooter game with heavy elements of the shoot-em-up genre.
The player takes role of a small ship, able to shoot in any direction, dash and clear the playing screen from projectiles, using a regenerating supply of bombs.
Gameplay takes the form of room-to-room exploration, wherein a series of procedurally generated floors are culminated with boss fights. In the process, the player finds new weapons, upgrades and power-ups, which last the duration of the run.
Score is accumulated during each session and can be spent to unlock new gameplay elements between them. As well, the starting hub can be gradually improved with the help of an assisting NPC.