Well, I'm sure all of you will be pleased to know, I've just finished the game as the End Boss.
That's right! When I reached the bastard at level 25, I made him forget his spells (so he wouldn't cast preserve on himself), turned him into stone, grabbed the statue, quickly teleported (!) away to level 1. After having setup a sort of "laboratory" in a safe place so no pesky critters would bother us, I "defroze" the Belzebub, made him learn Possess and Teleport, and Entombed my original adventurer so he wouldn't kill my buzz. Then, I body-swapped into Beelzebub, e.g. playing as the Big guy, I teleported from our "safe haven" and possessed some critter. BAM. After all that, I was prancing about as the Beelzebub himself, while my original character rotted away in self-imposed exile in a tomb :-D
Then I just went ahead and entered the final level (aka victory level) and accepted the congratulations. I wonder what the villagers thought when they saw me...
And that's it I think, there's nothing left for me in this game :-D
Also, some screenshots so no one would call me a dirty liar.
On a separate note, Pandora version of POWDER is by far the best one available. It's both portable and playable with a keyboard. Best of both worlds. Big thank you to Magic Sam for porting the game and to Jeff Lait for inventing it