Picked this one up on the Steam Autumn sale, and I have to say, I'm really impressed by it so far. Heard good things when it hit XBLA, open world zombie survivor game. Build your home base, build your outposts, gather resources, etc. Put 4 hours into it so far and I'm feeling like I've barely scratched the surface, game map is large (and there's already another expansion DLC available as well.) 13 bucks on daily sale, dropped to 9 once in a flash sale (I bought it for 13 and definitely feel like it's worth the money.)
http://store.steampowered.com/app/241540/