Don't know if it's intended, but it really, REALLY looks like Revenge of the Titans. The image makes me think of a demake.

This game is sort of fun, but PLEASE remove the mute music button re-enabling everytime you leave/enter a level.

This is a very cute game, but I found that two design choices from the creators bothered me. The first was giving us no hint whatsoever about what was different about the new aliens or monsters or whatever little blobby things we're fighting. Each course, for me, was very much dealt with by trial-and-error because I couldn't mouse over the "upcoming" window and see that the next set of monsters regenerates, or goes faster, or whatever.

The other design choice was that you didn't just get the money they dropped. Instead, you had to pick it up each time, and that became old very quickly when I was scrambling to grab the cash so that I could make adjustments to my towers before the aliens passed them by. It lent, for my game, at least, a tone of frantic to a game that would otherwise have been a nice, relaxing diversion.