This is thoroughly enjoyable. A nice spin on the idea of "Missile Command" with various upgrades. Nice sound and graphics although I find the music to be annoying, but thats a slight nitpick.
For me, the thing that really detracts from this game is that its too bloody hard! hardly any of the upgrades are effective especially when the successive levels difficulty seems to far outmatch the number of upgrades you can get in place, and very quickly, the game ends. Enemies falling on already damaged areas of the city still counts towards damage and means you cant effectively mount a defense unless you can protect the whole city, plus the whole "collect bullets to be able to fire back" thing is a good idea on paper, but in practice, when you have more enemies that you can shoot on screen and they dont fire at you so you cant shoot them.... yeah, quite annoying that ive lost levels because of that, even though I have fully charged machine guns and flak cannons that dont fire independently.
All in all, this is good, and the nice touches that are there make it really original and challenging, but the difficulty is set a bit high for my liking and I cant see me coming back to replay it simply because its not enjoyable to lose to what I think are oversights in the design of the game. however, 4/5 for effort! we need more developers like this making games like this that push the boundaries instead of idle games