In Atom Zombie Smasher, you get control over helicopters, mercenaries, snipers, bombers etc. and your aim is to restore peace to cities by annihilating growing zombie infestation. The game is played from a top down perspective. You can read more from our past article in which we covered the game few months back.
The game can be purchased from Ubuntu Software Center for $ 9.99
[Many thanks to David Padron for the info]