I liked this one. The controls felt a little bit clunky at times, but I think it's got some cool concepts to work with. I like the idea of a free form tower defense style game like this where you have to build your own maze. The sound effects where also nice and juicy.
Took me a minute to figure out there was more options than just the walls, but played 3 rounds and had a lot of fun once I figured that out. Good job. :)