I am not sure what do you mean zenox98.
If you want to see my game the link is:
I have this problem even i use the platformer template.
The player is out of control,
and i think the problems are vectors (x and y)
But for example in Chrome it works good...
I include a picture that shows what vectors i mean.
These vectors often are not reset when they should...
I am not proficient in English - i hope i write about my problem quite well.