Kirby Super Star Ultra/The True Arena

This mode is unlocked after completing Helper to Hero once. It's a remix of the Arena, featuring only the bosses that are new to Ultra. There are only five regular tomatoes, instead of Maxim Tomatoes, to heal Kirby between fights this time around.

The first six bosses are in random order: The "Final Four" are always in the same order:
 * 1) Whispy's Revenge
 * 2) Lololo & Lalala's Revenge
 * 3) Kracko Jr.'s Revenge
 * 4) True Mid-Boss All Stars (Mr. Tick Tock, Grand Wheelie, Phan Phan, then Fire Lion)
 * 5) Kabula
 * 6) Kracko's Revenge
 * 1) Masked DeDeDe
 * 2) Wham Bam Jewel
 * 3) Galactic Knight
 * 4) Marx Soul

Though Hammer and Rock are the standby boss-killers, it's hard to berserk through everything with Hammer, and Stone has it's own difficulties. Marx Soul is pretty adept at slaughtering Stone-users trying to take him down from above, Stone isn't as easy to use against the Krackos, and Stone can't even be used at all against Lololo and Lalala.

If you're going to try to go the entire thing with just one ability, Yo-yo seems to be your best bet. Gazer Spiral works wonders against Marx Soul, Wham Bam Jewel, and most of the tougher bosses. That move along with Break Spin can provide temporary invincibility in tight spots, which you'll find yourself craving particularly often in the fight against Marx Soul.