sorry i mistake ( i dont know why i cannot run so fast and i`m the only one player play so slowly ) that is the mistake i make it now right sorry for my mistake
It depends on who is the host of the room. Maybe his connection is better/worse than yours so it makes you lag out. If you are the host, your connection is bad, even with DSL.
I find when playing that before i can even make my first jump, someones already halfway through a level. My speed works pretty well with every other game, so I don't know.
I lag a lot too. Like when someone is going the same speed as me, they go faster, and when I finish first, the person in second finishes 1st. Lowering your in-game quality might help and disabling your javascript might help even better. Try using CCleaner and scan for viruses and such.