hello! im on mac and when i get to the beginning i can't seem to start any levels? all of them are locked, including the one i see everyone else select with no problem, am i missing a puzzle?? 
I personally don't have a mac so I'm gonna fix this problem on my friend's computer. Might take a while... But I'll let you know if I update a new version. Meanwhile, you could start this game again to see if it works this time. It may be some kind of delay of writing the savefile that cause this problem.