Excellent
Fantastic, I'm glad this finally got on the front page. Took long enough, got me thinking that it'd been ignored by the staff.
I don't normally play tower defense games because they all seem the same to me, but I'm glad I gave this one a shot. The balance between difficulty and enjoyment is absolutely spot on, so well done for getting that right - its not an easy thing to do. At first I thought only three tower types would be limiting and boring, but actually, restricting the tower types and where they can be placed gave the game a whole new level of simplicity that made upgrading and buying towers much more enjoyable.
I hope you make more games, maybe you can try out a different genre next? :)