Thanks Ran for playing and reviewing!
The game is made in HTML5 and Javascript, no engine was used. I don't know exactly why the game does not work in Firefox but it is related to the sound. Actually, the game works locally on my computer in Firefox, even if the sound is broken, but nothing works when I upload it to Itch.io. So finding out what is wrong is almost impossible for me. Someone at Itch.io should take a look at this...