Pretty good.
You've added a lot of features, which in a way might be a bad thing.
What I mean, is that it could be considered too complex.
This isn't an RTS. Don't try and make it look like one - in my opinion, mining resources doesn't work quite so well in a tower defence game.
However, I like the huge range of towers.
This game stands out from the other TD games, and a lot of hard work must have gone into it.
By the way simbrian, stop boasting and bragging about how good and useful you are please.
XD