Meh.
I didn't like it all that much, I liked the first one alot better. The walls were pretty cool but the fact that I couldn't make a maze or stratagize all that much like in the first one really sucked. It was frustraing when I thought "hey I'll split up the enemies at this fork in the road and then blast them, then there will be alot less on either side for my turrets to deal with" and then found out that every enemy in the game decides to take the same route making my stratagy useless. Simply improving on the original formula would have made for a much better game, I mean, that whole "build a maze" thing in the first one was what made it so good.
On another note, you idiots need to learn what critisism is, it's almost like any constructive review detailing why they didn't like the game is considered usless while any review that has 10 with "LOL i is lik da game" is considered helpful. You guys need to stop being a bunch of nazis trying to get rid of any opinion that isn't yours.