I agree with Wolf, this is simply lacking any type of polish demo or not... and it needs to be greatly cleaned up before being released as a for-pay game...
My take
1) Overall, this is a good variation on the tired realm of tower defense
2) I've learned that kongregate is full of kids who yell lazy programming with no idea what they're talking about...
3) Real criticism: No matter how little time/budget you have, you HAVE to beta test a game... even on personal projects that don't see the light of day I still have people beta test until I'm convinced its as good as it can be.
4) As much as its overused, I would try and work out an alternative point system than just "play until it becomes infinitely hard". It is already better to let people fight over high score than all dead-ending at some point with the same score for having an equal number of kills.
I'm giving this a 5/5 not for the game itself, but because with a bit of refinement (+ winnability) and bug fixes, this could be a great game.
I kind of have to agree, it becomes very repetetive very fast (especially since 3 or 4 rounds can pass by beore buying anything... then the next purchase takes even longer).
Also, why does the game lag when there's like 10 units on screen, no offense but that's not really a large number...