The setting also lends itself to the sort of environment where one really has to use one's imagination. We don't have photos. We don't even have statues. What maps we have are incomplete. What histories we have vary widely, and have been flavored with hearsay. There are Gods. There is a nearly omnipotent demigod for a main character. There will be monsters to fight, and treasure to steal, and a Kingdom to rule. Plenty of smite. And plenty of smut. With ample magic to please any palette.
As an added bonus, everyone who could possibly own the copyrights and trademarks on the Epic of Gilgamesh have been dead since before we started actually recording history.
Picking an established (albeit messy) canon allows me as a game developer to just start writing up database elements, and the connections between them, without getting myself too wrapped up in having to make all of that up from the getgo. As the exercise is to build the game engine, I want to make sure it can handle all of the interactions of a mythological story in a way that is both satisfying AND plausible.
Later, with game engine in hand, I can write a new world from scratch.
Each of the tales of Gilgamesh will implemented as a quest line in the story. You can pick or chose which ones to complete, and when to complete them.
Another nice thing about Gilgamesh is that while we all remember hearing about it in school, how many of us have actually READ the Epic of Gilgamesh? So I have a free hand to interpret the story and the characters in a way that is both true to the legend, while at the same time engage in a satisfying creative endeavor in of itself.
The player in the game will be a Demigod King or Queen. They will start off in control of one of the fair-to-middling city states of ancient Mesopotamia. As the character levels up, they will gain magical powers that will help them on quests, make a lot of money, and/or take over the world.
While I will drop in the canonical story line from Gilgamesh, I'll also be dropping in some original stories that allow players to take the character in a different direction. So while a history buff can run through the game making all the "right" choices to re-create the original Epic, other players can decide ... well... not to.
Say for instance you decide to NOT kill Humbaba at the end of Tablet Five? Meh, that doesn't change much. But what if the player decides not to spurn Ishtar? Well that kind of throws her off from sending Gugalanna now, doesn't it. And if Gugalanna wasn't killed, Enkidu wouldn't have thrown that Bull's leg at Ishtar, so why would the gods bother killing off Enkidu? Unless there is some adventure of Gilgamesh and Enkidu that leads the Gods to punish the two in a different way.
Rather than map the specific events in the story, I want to map out the causes and effects, and allow other causes and effects to also be explored. The original story of Gilgamesh will be one path through those cause and effects. But not the only one. And certainly not the "correct" one.
I also want to be able to demonstrate that a pure text adventure can be as fun to play.