Hi again,
I replay quite a lot to your game. And it seems that your multiplier is a bit buggy after the first game. For instance if i end the first game with the multiplier to x4, when i complete the challenges on the second game it will go direct to x6.
"Your browser isn't storing your scores for some reason". That's totally it for sure! I wonder if the bug I have just described isn't related to the same issue (If the reset of the multiplier is made after the saving)?