I beat the first level then the screen greyed out to the upgrades screen and I couldn't click anything to proceed - although the game hadn't frozen or anything... just a UI bug.
The game itself seemed fairly uninteresting, from what I saw of it.
the music was okay to fit this type of game , with a tower defense game the enemy minions aren't suppose to overlap each other,the font is quite annoying to look at ,you should write names under neath the minions and when having your mouse over the tower why does a black dot just appear.
When you click the menu what i recommend is to say pause .
with the special abilities you should put a info of what they do.
This game has nothing special to offer. There are much more better games in this genre.