This game is incredibly simple. It is very easy, and needs a skip wave button. This would make it faster paced, and also more challenging. Multiple waves at a time is fun in every defense game.
basically, i've been playing this game for about a month on a different site, and it pisses me off that i have to restart. still an amazing game, though.
pretty slow i've got to say, but good stuff. I agree with everything else thats been said, but a minor detail: The sound begins every level as "on," is there some game-wide setting that could be implemented?