ActRaiser/Fillmore

Boss: Centaur
The Centaur only really has two attacks. It occasionally will strike with lightning bolts from its spear, but each lightning attack can easily be anticipated by the blue glow on the tip of the spear. When the lightning is about to strike, simply move to the left to avoid being struck. The Centaur's only other attack is to charge with the spear, but this is also easily anticipated because before charging it will always lower the spear. When this happens, just go near the cliff on the left and kneel to avoid being hit. While kneeling this way, keep striking the centaur with the sword. Keep up the attacks and the Centaur is easily defeated.

Boss: Minotaurus
The Minotaurus will jump up and disappear off the top of the screen, and then fall back down and attempt to land on the player. After landing, it swings its axe, which sends a ghostly axe flying across the screen. To avoid being hit, don't stop moving. Walk left or right while the Minotaurus is off the screen, and then when it lands, be sure to keep your distance to avoid its long reach. The flying axe can be avoided by jumping towards the Minotaurus, which will also bring you within striking range. Get a couple of hits in before it jumps again, and then repeat the process. Also remember that using the newly acquired Fire spell will make the player invulnerable while casting, so its good for a couple free hits on the boss.