To defeat the Centaur boss, ride him five times until he gets dizzy, then mega punch him in the face.

In the first level you will see some dummies to hit. Jump on the log they are hung on, then jump again and use the mags by jumping and pressing DOWN and hitting. Phil will raise you higher so you can get the coins and extra life on top.

To access any level, enter one of these at the password screen:

Level                     Password
Hero's Gauntlet           Hydra, Medusa, Shield, Medusa
Centaur's Forest          Centaur, Herc's head, Minotaur, Archer
Big Olive                 Centaur, Shield, Hydra, Herc's Head
Hydra Canyon              Shield, Helmet, Shield, Soldier
Medusa's Lair             Archer, Pegasus, Archer, Centaur
Cyclops Attack            Helmet, Pegasus, Herc's Head, Archer
Titan Fight               Soldier, Shield, Shield, Lightning
Halls of Eternal Torment  Medusa, Soldier, Centaur, Pegasus
Vortex of Souls           Soldier, Lightning, Soldier, Centaur
Full Motion Videos        Pegasus, Soldier, Centaur, Soldier