New version, insane difficulty, Archeos only casts freeze spell (7-8 times in a row). I cleared all the monsters and he couldn't be killed because he didn't spawn new ones.
Screen: http://oi64.tinypic.com/2lc30jl.jpg
It's fixed now in 0.91. ( How could you unlock insane difficulty with bugged archeos ? )
It was bugged on Insane, I finished hard mode normally on previous version and played insane on new one.