As I suspected, it's because the game is running on low FPS. I didn't use a physics engine for the game, but rather made a simple AABB collisions instead (checking if the rectangles intersect). What happens is that since the framerate is low, the time difference between each two frames becomes large and subsequently the character moves a bigger distance each frame compared to someone playing to 60 FPS. I thought I would fix it before by limiting the minimum FPS to 20FPS (the game will just hang if you are playing at lower than 20FPS). For now, you can play the desktop version if you want. If not, fortunately fixing this is a matter of changing some numbers really and I will look into it later. Thank you for taking the time to record the video. I really appreciate it. Have a nice day!
PS: Nowadays, Edge runs faster than chrome and uses less ram. Besides having to change the search engine, I had no problem switching the browser at all. Maybe you should try playing it on Edge instead.