Oh HELL no, that's just cruel man. I can and have beat it alone on legendary, but without dying? ....no... no way.. can't be done.. CAN NOT be done.
Anyway, hardest boss goes to The 2nd level boss in Sub Terrania for the genesis. It's a giant floating head that uses tentacles to beat the living hell out of you, and this wouldn't be so bad if you werent stuck in a room that's pretty much big enough to merely fit him in it, nevermind you and your ship. I think I broke 3 or 4 controlers thanks to him.