This indie game gives you a birds eye view of zombie infested cities. Your job is to evacuate the civvies while dropping ordinance on the infected (yes nuclear ordinance is included). Other fun anti zombie implements include infantry and demolitions (that's as far as I got so far). The game is fun and lighthearted. While I am not sure it will give Magicka a run for its money, it's still a blast.
There is a coop mode and I am looking for someone to play with (look me up on Steam or TS)
There is a free demo on Steam. The game is $9 and downloads in a heartbeat (40MB). It appears to be laptop friendly too.
P.S. If you do get it, once the game starts and you are prompted for your player name, do not use the |TG| tag bars - it will crash (or at least it crashed for me).