Sucker I am! Bought it, and you are all Right On; it's a $2 game. it is also difficult, and I have yet to get anyting better than 'just barely surviving' and one stars on the first few levels I have tried. Maybe I am missing something, or just suck.
Def wait for a price drop. Pretty average/ above average TD, but worth playing for sure.
My main gripe? Add a Fast Forward button or similar; 40 waves took me forever. the creeps are slow as molasses. Oh, there is a rewind/ restart a wave button, but it costs in-game currency. Just find it odd that they added a rewind, and no 'Faster' button!
Off topic; i find Stellar Wars to be similar in difficulty. I must suck!