I really like the structure of this game, where you get some of the story than do an escape room that's a good loop! while I do think it's clever idea to have the heart beat spell out the code, i tend to be quite tone deaf so i wasn't able to understand it unfortunately I'm sorry , I would like if there was some sort of visual indication to help and distinctly different noises. I was also struggling to understand the X symbol as i thought it meant times like blank x green, would mean 0 X 8 = 0. I think it would be better if it there was some message saying like count green - blue for example, so that it's more clear to understand.
I also like how well you created tension in the story, the sound design and especially with the time limit of the final puzzle, I think that worked very well. and as I was replaying a few times to try and get to the end, i thought the humour of the speed run ending was well done with the sudden tonal shift.
also I encountered a bug where i was stuck in a loop talking to monika in case you weren't aware that happens and I'd also like Nyx to be expanded on as I didn't know what relation she was to the protagonist, guessing i thought she was monika's alter ego but nothing came of it.
overall good effort though!