It was cute.
Too easy for my liking. Got as far as level 6 before getting bored and giving up. Every level was just build sniper tower, upgrade to max, build another repeat ad infinatum. got tedious quickly. Also, one tower can kill everything (maybe it will be different in later levels) which is a bit boring. Plus, there arent any tool tips for which tower is which and its attributes which makes you choose based on the picture alone. not easy.
Other than that, good. and the mini game was alright.
But make it more difficult!