So I had a real hard time deciding between this and Grand Theft Auto 3/Vice City.  This wins due to epic theme and the fantastic alien graphics.  The game play is astounding.  This game is moderately challenging and entertaining to the end.  I cried the first time I beat this game because I didn't want to Samues's adventure to end.  This game is it.  It doesn't get better.  I'm gonna go cry now.