I like it overall, but it certainly needs some tweaking. Backtound buildings flicker. controls are little awkward(to me). and it was very clear how to finisht he level. It's also a steep learning curve without teaching the players how to be effective using there tools
I would suggest remove the mine and turret first round and introduce them with consecutive levels. just let players get used to the basic controls first level.
Maybe add some attacks to stun opponents.
Otherwise it's looking nice :)