You're a Munchkin. You don't do anything halfway. Sure, you could just go straight down to the bottom of the dungeon and fight the boss, but you'd be missing out on all the extra cool stuff to find. Where's the fun in that? Why not take a trek off to the side and see what lurks there?
The Side Quest expansion for Munchkin Dungeon gives players plenty more to search out. Along with new Threats, Rooms, and Wandering Monsters, it also introduces Side Quest tokens. These are set out at the start of the game and players can earn them by completing certain achievements. Each one will up a Munchkin's Fame at the end of the game.
There are also two new heroes ready to enter the Dungeon: Rangers and Halflings!