Very cool and engaging tower defence, the map seems very well designed by not many insanely overpowered positions. The waves seemed extremely balanced too, each wave around the end getting extremely close.
the merging concept adds a lot too, but I wish I could see the "kill count" of towers to see if they are effective in their placements. also the screen-shake is a little much but that's pretty much my only complaints. definitely a 5 for fun