Awesome, but you shouldn't start with two badass characters, where's the level up system? Aso, the monsters need a health bar, I thought the cat in the giant green blob would never die! :S Awesome, though. 5/5
Here's a bug that I found to make your life easier: Go to Rampage mode, save and exit, go play the main game. You will have all the weapons with lots of ammo (the same ammo the Rampage Mode gave to you).
It's working fine for me. Try uptading your flash player, uninstaling than re-installing it, forced refresh (ctrl+f5), another browser, another computer, clear your browser cache, cookies, whatever.