quantity not quality counts here. the upgrade progression is baffling to say the least.
Still, basic qualities of a TD are present.
3 of 5. also, limited number of towers is stifling.
This game is very reminiscent of the game "Warning Forever"
See (http://en.wikipedia.org/wiki/Warning_Forever). I recommend this game, as well as Warning Forever, to all fans of manic shooters.