What is the Wizardry IV of literature?
>>8248864
toilet
What is the Killer 7 of literature?
Probably the rosc passages in the Tain Bo Cuailnge.
The Tain is a genre of gaelic sagas, and particularly there is a cycle of these sagas that center around the hero Cuchulainn. While the Tain Bo Cuailnge is already extremely difficult to piece together, there are passages of rosc - which typically occur in times of prophecy, or important conversations in the book - that as of yet have been untranslated. They can be understood, in brief moments of clarity when studied by Gaelic scholars, but more or less cannot be effectively communicated in modern English.
As far as "most difficult piece within the Western canon that becomes even more difficult because of cultural differences surrounding meaning" I think that's probably not a bad parallel. As I recall, Wizardry 4 is borderline impossible, right? Instadeath ninjas, you get like nine spells tops, all of your summons are useless, you are openly declared by the game to be the bad guy, you're punished for dying, which means dying compounds the problem...
It's tough though. I find parallels between video games and music much easier than parallels between video games and literature. Structure isn't studied quite as much in literature as it is in music.