The stutter made this unplayable. The horizontal camera stuttering happened in Firefox, Brave, and Chrome.
Beyond the stutter, having an intro that is around 3 minutes long, is unskippable, and plays after you die, is something you should reconsider. Everything you said could be consolidated in about 10 seconds, or with some visual cues in the scenem without any voice over needed.
Thank you for trying it out, if I may ask- did you also try to refresh your browser after starting the game? While it's definitely an issue I have to solve in the future, that seemed to help others who played the game!
And about the intro, I fully agree, the intro is quite long but it's also a part of this specific experiment for my thesis so it's intentional- but- I did add a feature that shows up once you've died the first time, you may skip the instructions with the Key that's showing in the Game Over Scene! :)