Are you able to use magic/tricks (e.g. a Teleport spell) to circumvent the final creature, and thus win the game?
The rules seem pretty clear on this:
No card or power will let you bypass this combat! The Boss ignores any rules, cards, or powers that would take it out of the Entrance. It can never be controlled and will never ignore a Level 10 munchkin for any reason, even if its card says it will. It always fights.
You pretty much have to fight the boss... while teleporting him away would be the Munchkinly thing to do, you'll have to slug it out with the boss.