The graphics, especially the weapons and blocks, are simple in an extremely satisfying kind of way, and the animation and sound form a nice picture of what's going on. The sound effects get a little annoying and some are odd, but overall it's good. it could have used more diverse music, though. The gameplay was very fun! I loved customizing my own tower, and when it started out symmetrical it ended up becoming really wonky. The system of leveling up weapons and different strength blocks was simple and easy to grasp, and the gameplay was pretty raw.
My only complaints are that the game becomes really hard really fast, and that it's hard to browse the weapons to see how each one works when you can only look at them and purchased them during a wave. Also, it was kind of difficult swerving the mouse down to one section to select a certain weapon. Keyboard shortcuts would have been welcome.
I also noticed a glitch. At around the 43rd level, I was taken to the screen to prepare for the next wave while the previous wave was still attacking me! I couldn't attack back, since I was only able to place blocks, but I was able to win by successively clicking Next Wave until it said I had completed the last one. When trying to return to the main menu, though, I couldn't, and the winning screen kept popping up.
Despite the kinks, I really enjoyed this game and thought the system was simple, easy to use, and very tactical.