This is a case of too many people listening to the critics. This was a wonderful movie.... Overacting? Penn was playing a schizophrenic who went through full blown psychotic episodes? And I enjoyed Mel Gibson's portrayal of a man who struggles with his own perceived failings but as a Christian believes in grace, forgiveness, mercy and finally redemption.
A nice distraction from all the space battles, zombies, crooked cops and gratuitous violence.