Jay is Games describes Nitrome's awesome Flash based FatCat! (click here for game)
It looks like a plain ole shoot-em up but it is a mind bending dual character control game. You control FatCat with WASD which is the fragile one with critical super blast (which charges up when he eats enough food prizes). You ALSO control movement and shooting this Owl with a mouse which is the shooter, and essentially the protector of Fat Cat.
If just shot stuff up that'd be one thing but the Owl is also responsible for moving indestructible blocks out of the way like a puzzle game but with the relentless scrolling screen, it is quick reflex based.