Just beat the Leaving Brazil insane challenge. Storm (Classic) is my go to... Allowed Spidey to take damage, which soon took out Daken and Bullseye with Storm's whirlwind counter.
Got 500 ISO sent out to 3 "Facebook" friends too, which was cool.
Yea, thanks for those rewards. They have been much appreciated.
I beat the Brazil challenge in a similar manner. I brought along Thor and Classic Storm. Spidey triggered her passive(s) when he got hit and I used Thor's red/yellow strikes to finish them off.
Once you get it down to the Thug, it's just a matter of making sure to clear out any blue tiles he lays down and hoping that any yellows that pop don't trigger a chain reaction.
At one point it was my Storm (with 400 HPs) versus the Thug (with 4000 HPs). I still won.
I have Thor up to level 50 now. He is such a beast.