Which version of the game are you playing? I didn't get ambushed all that often in NES and DoS versions, and actually, I'm not sure if the amount of getting ambushed depends on your stats (maybe speed or luck). I didn't really find any of the Pandemonium enemies that hard, except for bosses. Golems or some other giant enemies take a while to kill, but there are ways to defeat them too (Curse, Berserk and Haste, and maybe Safe and Blink). What I'd suggest is that you leveled up your characters more.