A good game!

However, there is a lot that can be improved upon. I bought the game, to experience more than just three levels, however... Six levels would be fine at the detail invested in this game.
First of all, characters should level - or something to improve them as days go by. A character sucking because shes pretty, and never improving over 2/3rds of a month? Cmon. Anyone spending night after night shooting is bound to improve!
Secondly, characters should be able to be moved slightly - even at the cost of reduced firing capacity. If the zombies compromise a level of defense, one moves. Seriously. Id strongly suggest a line drawing element to the game, rather than preferred aim to make it less watch and more play, especially during long zombie episodes.
Thirdly, some kind of high score list... For something to aim to beat. Even your own personal high scores! Nothing? Seriously?
Lastly, iOS 4 multitasking.
Id be willing to pay for an expansion, if thats what itd take to get these additions. :)
Great job for a first try, but too non-interactive to play for long.
Id recommend this only if you have a dollar to spare, otherwise... Save your money.

Entrée about Zombie Defense