Max Brass and Hedlok took me all morning to do. I recommend using an ARM with either the Electric or Ice attribute. Using the Chillas made all the difference for me. Land a charged hit and immediately go for a grab.
I tried a couple times and got me arse handed to me. Then I dialed it back to 3... and am getting me arse handed to me, but it just takes a little longer: 3 rounds, instead of 2.
Well, I just beat level 4 with Master Mummy! Thanks for the tips, everyone. Paying attention and playing defensively by watching your opponents punches and jumping helped me a lot.
I haven't picked a favorite character yet. I really like Mechainca and Master Mummy, but I haven't tried everyone yet. So far, it seems I do best with the heavyweights. I'll have to try lvl 4 with Master Mummy!
Shielding is your friedns and can allow youto launch counter attacks. It took a while to incorporate this into my playstyle but it's paid off. (Mind you i was wrecking everyone anyway)