Damage the following Bosses with the corresponding technique. A sound will confirm correct code entry. Defeat the boss, then the next level will then be in Hard mode.
BOSS - TECHNIQUE Forest Shredder (Wolf Kingdom) - Reflect his dynamite back at his face. Wolf King (Deep Underground) - Wait for him to stand on top of a breakable floor block. Hit him until laughs, then drill attack the floor so that he falls. Axel Gear (Return To Zephyrus) - Have him get hit by the tracking purple ball attack that he uses.