Thank you for the translation! I saw the note and just the fact that you are continuing this is amazing! I have no skills to offer, I am terribly sorry that I can not help you
Don't worry, take your time with doing this since you did mention you're using your free time. Hopefully down the line you'll have extra help on this and the wholesomeness will continue.
It would be very hard to create smells in VR (at least harder than visuals or sounds) so using odor memories as a basis might be an easy and effective way to solve the smell issue : zombies smell bad and rotten = the player will smell the worse rotten stench he ever experienced.
@Glomoro - maybe it's the "reduced realism" setting that helps here? I guess not. Otherwise, people would need gas masks to challenge this floor.
@zenyo - I'd say using the users' own memories is harder than just inputting recorded smells into their senses.
SAO's Alicization arc is the only one of all the VR stories that claimed to use this technology.