The "tutorial" isn't actually a tutorial, it's just a series of instruction pages. An actual tutorial should be something playable where the game walks you through the various features and controls.
The timestopper and bomb should be mapped to keys that can be used by the right hand (or freely remappable, if possible), since the left hand is too busy with WASD. As it is, those two game features end up being unreliable at best, and nigh-impossible to use in the split second that it could actually save you.
Garbage disposal code needs to be optimized, I think. The game starts to slow down after a couple of minutes, but starts working fine again when I close and reload the game.
I don't know if this is a bug, but I managed to get two slow effects on the final boss, and his meter just froze right there. The poor guy didn't even get to attack me once. Kinda takes a bit of the satisfaction out of the victory, you know?
@nathangibbs: Just start a wave without any towers and watch where the bloons go. Preferably the first wave, so you can restart the map without too much wasted effort.
The game does not tell you when you can start eating a larger size of dog. It needs a display that tells you the largest size you can eat at the moment. Or at least make it so your dog suddenly inceases in size when you can start eating bigger ones. Something that tells you you're not stuck snacking on little brown chihuahuas anymore.