Hi, thank you very much for the feedback! I'm really glad you liked the dialogue, and yes, I made it from scratch, no tools.
I never did dialogue in my games before, so I didn't know what I was doing. I made a singleton to manage the dialogue and wrote a function to render the text. The final script has over 3000 lines and 1000 await calls, but it worked well for what I wanted. Normally you would store all the dialogue in a JSON and load what you want as far as I know.
For the secrets, if you are interested in going back, there is a hidden room in the first level (just hug the walls in the corridors) and there is also secret dialogue at the end if you keep messing with the "zero deaths mode" during the cutscene. At the beggining of the 2nd level, if you stand still in the apartment, God will start getting anxious and punish you. In some parts of the 2nd level, if you mash skip during the dialogue god will get pissed too. And finally, there is a secret corner at the end of the 2nd level that tells you how many secrets you found. I wasted way too much time making secrets...