Yeah, i unironically investigated about the many worlds theory and John titor after the first play to understand every refference.
Also i think you forgot to make the game that is the gap between existence and milker(i think we got a flashback of it story-wise in farewell my hapiness, or it was an Existence flashback, i don't remember seing that scene there). Would have liked to see a bit in depth look at Existence medieval and magic world.
Naz is a great character and would have liked to see more about her(maybe she could overthrown CC in popularity, but already "Null" seetled it), maybe her world made her hard on the outside but she still has feelings, also fun to see her and CC insult each other, kinda childishly. Also(spoiler) i guess Naz was born in existence? or got her memories deleted and got a different life?
I would say about more of Lisa, but just another Lisa. "Zero-One" Lisa arc was perfect i may say.
Well, anyways, i'm looking forward any work you do, even if it is not from Hapiness multiverse.
And funny enough, Mc being cynical made him lose all what Hassan could only ever dream of, getting a harem lol, if there is infinite timelines then mc surely made the harem in at least one lol.