Shutshimi

Shütshimi is a randomized shoot'em up about a muscle-bound fish with memory problems defending the seven seas.
Armed with your trusty bullet-morphing shotgun, defeat or navigate through waves of enemies and collect powerups as you battle your way through each of the game's bosses. But there's a catch (there's always a catch): you've been cursed with an incredibly short attention span. Combat waves and upgrade cycles only last 10 seconds a piece, so you'd better act fast!
But wait, there's more (information)!
Fishy Features:
Endless waves, endless fun!
Rapid-fire gameplay! The rules change every 10 seconds, so react quickly!
5 different weapons to choose from!
Over 40 upgrades to acquire! Combine upgrades with different weapons for interesting combinations!
Hats! Over 30 of them! Most hats unlock hidden "Hattributes" which modify gameplay even further!
Full keyboard and controller support! Play any way you like, as long as it's either of these two options!
You can smoke underwater!?
Leaderboards! Compete with friends and foes for the global top score!
Local Co-op! Work together or screw each other over when competing for the top score