Original, entertaining, challenging
This is one of the best things ever made for Newgrounds, I believe.
Fighting as your favourite Newgrounds character (In my case, Piconjo) and kicking the crap out of everyone else is just the thing you need to kill some time. I had a really hard time at Convicts last battle, but I managed to defeat them all at last. I got pretty frustrated when he kept transforming into Tankman or Salad Fingers, as I find them completely useless in that battle (I use the "gang up on one character and use your aerial skillz to kick the living shit out of him" strategy).
Good work, and I hope to see a sequel!