No second player for me but I can still rate the game on its merits. Really good solid platforming engine you built here, collisions are great, framerate is smooth, feels responsive, graphics are actually really great. One thing which could be improved, would be nice to jump higher if you hold down the jump button (or jump less if you're just tapping it). I recommend looking at the Sonic Physics articles (http://info.sonicretro.org/Sonic_Physics_Guide) for a really good platforming implementation - certainly helped me!
this is not new concept, not super polished game. I've got a feeling. that's something wrong with this game. Maybe, because I'm playing alone! )) my right hand against my left hand! Deathmatch!)) Come on Lefty! Kick Mr. Rights ass! Bring it on! ))
Overall, good job :)