Dead Effect. It's a fun but flawed FPS. I just finished the fourth or the fifth mission, this level was a bit laggy for some reason, and full of grenade throwing enemies which was an interesting mix.
I paid 49 cents of Trading Card money for it and it feels like a bit of a steal at the moment. I was a bit hesitant with it being a mobile port, but it looks great graphically, the controls are responsive, and the gunplay is solid enough and there is plenty of zombie gore to be had. Throw in a few gimmicks like good ol' bullet time and a attack that hurts any enemy around in within 10 feet or so, and you've got pretty fun gameplay. Mindlessly mowing down zombie after zombie can be fun and don't let your parents, local gaming forum moderator or anybody else tell you otherwise.
It does have some flaws, you can't jump which is annoying for obvious reasons and because of an enemy that crawls on the floor that you can get stuck on, certain enemies can be bullet sponges, and the game's idea of difficulty seems to be completely filling rooms with zombies, occasionally in very cramped areas. Of course if you like run n' gun arena-ish FPS's then that last point might be a positive. Level design is nothing to write home about, it mostly involves getting from area A to area B (usually an elevator) while fighting roomfuls of zombies, pretty generic FPS starring zombies on a spaceship stuff.
On a mechanical level, I've experienced no crashes and only one area (part of the level I just finished) had any sort of performance issue. The music however is much too loud, to the point of overloading and becoming distorted, along drowning everything else out when active. This can be fixed by turning it 75% of the way down, but it's sort of shocking that the audio levels are just that bad in the first place and require turning it down that much.
If you want a cheap B-level FPS then Dead Effect is definitely worth picking up, though I'd recommend waiting for a sale as it IS a B-level FPS.