Hi Pentixel, thanks for playing and leaving the feedback and idea.
I also found the bug:
when the player dies i reduce the sound and Gamespeed to 70% or something, and start a 3s timer. the timer then sets both sound and gamespeed back to 100%. If you press the restart button before 3s the timer has no chance to set it back to 100.
Now I set the sound and gamespeed back to 100% also with the restart button press