Are you a fan of games like Twisted Metal and Vigilante 8? Hell yes? Well then you'll probably enjoy Zombie Driver (you'll probably enjoy it even if you don't like those games)
The game has 3 modes, Story Mode, Blood Race, and Slaughter.
Gameplay is very simple, you drive, you shoot your weapons and you kill zombies.
Story mode is basic but fun, you are a civilian who has survived the zombie apocalypse and end up working for the military, essentially doing missions they can't get the green light for. Most of the time spent in story is rescuing civilians and mowing down zombies. Each mission has a main objective that you have to complete, and a side objective that you can complete for bonuses (money, upgrades, cars, etc.) You can unlock upgrades, which you then use your cash to purchase for your car.
In Blood Race you are pitted against time and other drivers. The streets are crawling with zombies and you are racing against other drivers and time to get to the next checkpoint (which adds time to the countdown). You get bonus money for destroying other cars, and zombies on the way.
Slaughter is essentially survival mode, you down increasingly difficult waves until you die, with each wave getting more difficult, the pickups also get better.
The cars range from practical to whacky, including taxis, sports cars, an ambulence and much more. Here's a screen shot of a taxi flaming some zombies
The toll on the wallet? $9.99 There is one DLC available, Summer of Slaughter but for $1.99 all it adds is a single Paradise Island type slaughter map. Whether that's worth it or not is up to you. I think 9.99 is a great price for the game...but the DLC could be cheaper, a fifth of the price for a single map is a bit much.