Place towers to strategically defend your base from the enemies, but watch your cash supply! Money is limited, though the less you spend, the more interest you'll earn. 3 levels to play, with 6 more to unlock.
This took me ages to make, and is the first time I've attempted to make a tower defence game. I have to say that although I found the basic mecahnics of a tower defence game realitively easy to make, all the little details (level design, sound, enemy balancing etc etc) really ate up a lot of time. Although I'm not ecstatic with how this came out, I'm glad I've made it. A great experience to make, but boy what a lot of effort. Enjoy!
EDIT - I've updated the towers and zombies a bit in response to the feedback, hope you find it a bit easirer now!