Its alternate title in the Nintendo DS version, "Mythos of Marge", is possibly a reference to The Legend Of Zelda.
Homer's outfit is a reference to the character Link from The Legend of Zelda.
Marge's outfit is a reference to Princess Zelda from The Legend of Zelda.
The chests which contain different items are references to MMORPGs, along with fantasy games such as The Legend of Zelda.
Homer refers to Marge as being "a sexy MILF", which Marge corrects by saying that the word is "elf".
The Mobbits are parodies of the Hobbits from The Lord of the Rings. Marge will sometimes refer to them as "hairy toddlers", which is a pun on the fictional character Harry Potter.
One of the Mobbits sometimes says that he prefers Narnia, the fictional land of the C.S. LewisThe Chronicles Of Narnia book series. It's either the Rod or Todd Flanders Mobbit that says this, since C.S. Lewis is a Christian book author.
Some of the characters and their costumes are from Earthland Realms, an online game in the Simpsons universe which parodies online MMORPGs.
The final level against Patty and Selma in the Xbox 360 version is a spoof on the arcade game Joust.
Upon entering the maze area, Marge notices the camera switching to overhead POV (point-of-view). Homer states that this is just like his favorite old sword-and-sorcery game, Dig Dug - which is neither a sword-and-sorcery game nor even set in overhead POV, at least not until the sequel, Dig Dug II.
He possibly meant The Tower of Druaga, a fantasy adventure game also made by Namco, or more likely Gauntlet by Atari Games, due to the similarity of how its "narrator" points out things like not shooting the food.
In the Xbox and PS3 consoles, the Dragon door looks different to the others. It's much more darker in the dungeons and the Orc Moe spawners are smaller. The dragon is defeated (in the first section of the level) by Marge sending the Mobbits to attack her, rather than Homerball slamming into her, he does still need to but in addition to Marge's act. Homer defeats the dragon by using Heli-Homer (in the final part).
In the PS2, Wii and PSP consoles, the dragon needs to be defeated by Marge sacrificing a Mobbit and Gummi Homer squirting her three times.
In the DS console, the dragon doesn't try to burn the houses down, and their aren't any Mobbits outside for Marge, Homer has to Homerball Dash into the dragon several times, the dungeon section isn't formatted the same as the others, Homer isn't playable in the dungeon sections, as he is a recruitable Mob Member.