Whoever said that the game "doesn't work on Safari" is wrong. I'm using safari on Mac OSX 10.8.4 and it works fine (completed the game). Don't see what the problem is.
Guys, to beat the Panda, you have to upgrade EVERYTHING. Then put Ken's special to shield, Rei's special to dynamite, then Annie's special to heal, and then Lee's special to stun. Stun the panda, place dynamite under him, and then put the shield onto Lee. Heal only when Lee is about to die. Once Lee dies, put the Shield on Ken, and then just heal and repeat. This should work. + this comment to keep it alive. :)
Thank you Insanecat!