I like the idea and it got me really panicking for a moment - in a very good way! The idea is simple but a great one and the execution is good. The effect of the walls wasn't clear to me immediately - why did it slow it down and not put it to an halt completely? Or why isn't it some kind of glue... well, that's just nitpicking by me. I also liked the music!
If you feel like it, leave me a rating and comment as well :)