That was fun - I was able to get to level 6. I liked that the "game over" screen shows how far the player got. I must admit that I didn't understand the game at first and it was only after reading some of the comments that I realized I could add towers to the map using the side panel on the left of the screen. I wish there were some sounds and music to add to the atmosphere. I do like the art style - especially the title screen. Keep up the great work!