Most of the time I access the game, I'm always moving either left or right without pressing any keys. It makes it far too difficult to play the game. Even leaving the locations and returning still yield the same problem.
As a workaround, try hitting the key used to travel in that direction. There's an old bug (that to the best of my knowledge still hasn't been fixed, cough cough cough) that causes a directional key to stick in the code. Perhaps the workaround they suggested for that one will at least make the game playable for you.
That's a but I know from the first beta. This isn't anything like that. It almost locks in a single direction. Even pressing the opposite direction doesn't allow me to move most of the time. Sadly restarting the game and the computer, doesn't help.
SRG- you are using Chrome which manages it's own Flash plugin. It seems to work ok for me on the same browser/OS combination, so try going through the uninstall process for Chrome and then reinstalling it completely.
(Woochi- the old bug is an Adobe one that we can't fix. It happens more often on Firefox.)