Nightmare mode isn't really hard, it just takes luck. Mind-numbingly frustrating? Yes. Hard? No. There's no strategy in nightmare, just hope the pieces fall in place for you.
It gets really annoying when you accidentally hover over one of your sumos with the mouse and make them eat when they're about to collide with an enemy.
I got a funny glitch. On the first cave, I was going in to kill some relic hunters, as was the current quest. The person I got the quest from gave me some backup: A bowman and warrior. I was doing the quest for the Phoenix, but for some reason I got a GUARDIAN bowman and 2 swordsman who helped me kill their friends! LOL.
What is there not to like? Fun and complex gameplay, amazing graphics, epic soundtracks, hilariously epic storyline and you can play it for hours. Definitely one of the best flash games out there.