Yeah, MOTS was the toughest game I played.
Level 14 took me two days to beat. But now, I have beat it enough that I know my way through all the levels as well as the Secret Areas.
A word of caution, watch out for the vornskyrs in level 12-14 I think. They are mean SOBs that hurt like hell, are imune to cloaking force powers, and are tougher than anything to kill.
So, if you need any pointers, just ask