Apparently, it depends on which browser you're using. If you use Firefox, you can use full-screen mode, but with other browsers like Microsoft Edge, you're stuck with that small window. I have no idea how to fix that, but thank you for letting me know!
That's painful. I would have added QOL after finishing the game and implementing the features, but I didn't even had time to fix the mouse bug, so QOL wasn't my first priority. Anyway, thanks for the feedback!
Thanks for the feedback! That was my first 3D game, so I had no clue how the lighting worked or how to fix it.
As for the difficulty, I can only imagine how hard it is not knowing where the hitboxes are, so I have to rely on feedback like yours.