Catalypse is a horizontally-scrolling shoot'em up where you guide your ship against the alien CLIO civilization through five big levels, including a moon base, an alien forest, dark caverns, and an ancient city. The levels are full of small enemies, both stationary and mobile. There are also bigger mid-level creatures and of course level end guardians. These include screen-filling giant creatures, robots and spaceships. On your way you can collect cumulative weapon power ups hidden in capsules. Available are angled forward shots, a backward shot, an angled bouncing laser, a powerful forward laser, and up to two hovering and indestructible satellites. Unique characteristics of the game include sampled speech in the introduction and an extended animated ending sequence.