I'm tempted by HOTD: Overkill - TLR but from the reviews I've seen it's really short with not much to do but upgrade the few weapons, and there's DLC on top of that to get everything out of the game.
I bought it. It has 4-5 levels in story mode. The first one seem long enough for a level, maybe 5-10 minutes, I didn't sit down and time it. Definitely short considering there are few levels, but it plays very will with the on screen thumbstick. There is also a survival mode.