It's a first-person shooter game (more like an arcade) where you move in a 4D maze and shoot monsters. If you are not familiar with the concept of 4th dimension, don't worry much, because the first levels of the game go in 3D, and you will get the hang of it fast enough. The maze consists of cells, and there are four types of cells in the maze: simple corridors, cells which regularly respawn monsters, cells which respawn ammo and health bonuses, and finally, the exit cell which you have to reach in the end.