Not realy i just did it an hour ago and it was simple i just put him in a mash pit and get 8000 points per arm move ^.^ now im 6/20 5 stars. i got 2 with leon.
Im on gamecube, but i dont want to cheat evil if i bought it for my bros ps2 cuzz like i hate the controler for ps2.
I probably don't remember much about Krauser on mercenaries then. It's been quite a while since I've last played as him. I didn't enjoy it :S.
I'm better off with Leon, Ada and HUNK.