Great concept, but it really needs some polishing. The levels are in need of some major balancing, and the prices need to be re-determined; the second and third defenders are almost-useless due to their price, and repairing is not worth the cost until the defender reaches the max level. The graphics are actually very well done, though.
Bubbles (the kind dropped from enemies) should bounce back from the edge of the bubblefield, instead of disappearing. That would make the repulser cannon USEFUL.
This is a great concept, but the levels do not seem as planned- out as I would like them to be. Level 25 is a great example; The goal itself is very straightforward, but the path you need to take to reach it is cluttered with spikes and such, making it no different from the scores of other platformers out there. I think you could have implemented this concept just that much better.
Hmm...I got a kill 10 seconds after I died, another one 10 seconds before the match ended, 30 seconds after I died. I also see other players jumping around the map, and I shoot at people 30+ times and they don't die yet. What is with this lag?