nice but...
it essentially gets boring after the walkers come in. (like who didn't expect them?) hit detection is way way off and is the main bug in this game. Another is that the turrets sometimes (and rather often) ignore the enemy at the very front (usually an infantry or tank) which essentially defeats its purpose of actually defending. This combined with the horrible hit detection gets frustrating when there's an infantry shooting in front of you and you can't kill him.
overall, great, but the bugs are major flaws.