To do this, you'll want hearts, the Instant-Death power, and anythig that does lots of damage or makes you run faster.
Bet hearts to lower the level on Chapter 24 to 0.0. Choose a strong weapon, and use the powers to run fast between trials and make short(er) work of the bosses, but save 1 Insant-Death attack for the final boss. Activate and kill. If you beat it in 11 minutes-, you can fuse weapons(like Twinbellows Cannon and Pandora Claws) to make the weapon, and buy it from the store.
During an air battle in Solo mode you can reflect an enemy's shot by flicking the Analog-stick to one side then quickly flicking it again in the opposite direction. If timed correctly the shot can be reflected back at the enemy.