Very Good but...
Well, I find it was kinda lacking. Graphics are nice, music isn't at all bad and gameplay is good.
Only throwbacks are...well, no ending level animation and Magic Towers. They are totally unbalanced. In fact you only need them and their upgrades. Arrow tower is only good for tutorial, after that you may as well forget it. Fire Tower is not bad, but unnecessary. Frost Tower I didn't even use it once.
Maybe for Arrow do it attack with more than 1 arrow at a time and may be useable. Fire should do splash damage and there should be enemies magic resistants so you can't do like I did, forsake all but magic towers and beat the game.