The way ladders screw with your jumping is pretty annoying, and has killed me more than once. I have the jump and climbing buttons separate for a reason — they shouldn't be interfering with each other. Otherwise, pretty solid game. The knockback is pretty massive, and some of the later challenges drove me up the wall, but those don't detract so much from the enjoyment.
You know, it's pretty dang awesome that you guys are being so responsive to player feedback, ESPECIALLY since this is a port. A lot of devs wouldn't even make a browser version, let alone be so attentive to feedback. Game just went from four stars to five for me.
Not getting the badge on the latest release version of Firefox, and there's something odd I've noticed — I have FlashBlock on, yet the game itself just automatically loads instead of giving me the option to enable it. (Yes, I click the other Flash object to enable the achievements system and such to work, that's not the issue.)