It's a fun, sometimes pretty, ride around the street but not that good for a road-trip.
The campaign took me a good three hours to complete, the other two modes were quite bland but I played them some. I had fun for the five dollars I paid but if I spent more I would've demanded a lot more. You drive a car that can have a variety of guns and run zombies over, sometimes you shoot them! That's about it. The missions are all identical with you racing here or there to pick up survivors with the occasional side mission that encourages you purge an area of so many zombies. These side missions are useful however as they can provide more funds of which to purchase the deadlier weapons of the game which leads to more and more dead zombies.
There aren't that many variants of zombies. There's the basic that doesn't do much but there's a lot, the hulk ones that slow your car down if you hit them, the ranged zombies, the boomers that explode on impact - this can be used tactically however, get near enough a herd of them and you have, my good man, a zombie grenade - and dogs that don't do much aside from get run the **** over. There's some cars to choose but the best option is the limo as it can seat the most survivors and, as such, is the most efficient of all the vehicles. The best way to complete, scratch that, survive the levels is to avoid the hordes bearing on you so it doesn't really matter if you have a vehicle with loads of armor as avoiding zombies is the best way to complete the levels. You can just say screw that and go on a rampage in a taxi however, choice is yours, ol' buddy.
I played for four or five hours and enjoyed it but I'd be lying if I said I did so in one go. I split the game over numerous playthroughs for, at most, fifteen minutes or so each time I played. If you can get it for cheap I say go for it but don't pay more than five dollars for it.