Cool game
I found the puzzles quite unintuitive though, I still don't know where the text you have to put into the 1st input field is, I had to look through the js file to find it. The IP one I might've figured out eventually, but I ended up looking through the code for that one as well, and then afterwards realized where it was hidden.
Viewing post in The Rollback jam comments
Alright,
In the video linked in the OSU! letter, the final text that appears is Neuro-sama's First Journey. And in the letter from "SunnyTrail," there are quite a few typos (maybe I should’ve made the typos more obvious). Plus, the letter mentions "summer" and "first journey" multiple times.
But honestly, this puzzle is pretty bad. I have no idea what I was thinking.