Boss Endurance is a game mode categorized as a Sub-Game. It has appeared in several Kirby games, starting with Kirby's Adventure. In it, Kirby must face every Boss he's encountered on his adventure on a single bar of Stamina, and starting with no Copy Ability. Some variants of Boss Endurance measure the time taken to complete the mode.
Boss Endurance is distinguished from The Arena in that, generally speaking, no Copy Abilities or rest areas are provided between bosses. Additionally, it is not typically required to complete this mode in order to earn 100% completion.
Boss Endurance has appeared as a mode in the following games:
Kirby's Adventure / Kirby: Nightmare in Dream Land
Referred to as V.S. BOSS! in Kirby's Adventure. The following bosses must be defeated in order:
- Whispy Woods
- Paint Roller
- Mr. Shine & Mr. Bright
- Kracko (includes Kracko Jr. chase-down)
- Heavy Mole (fully restores Kirby's stamina when defeated)
- Meta Knight
- King Dedede
- Nightmare (both phases)
In Kirby's Adventure, the ending and credits sequence will play unaltered after defeating Nightmare.
The Kirby: Nightmare in Dream Land version has a timer like The Arena. Clearing this version of the mode will display an image of Kirby with a trophy, captioned "You're the Champion!", along with the clear time.
Kirby's Dream Land 2
Simply labeled BOSS in-game. The following bosses must be defeated in order:
- Whispy Woods
- Nruff and Nelly
- Sweet Stuff
- Ice Dragon
- Mr. Shine & Mr. Bright
- King Dedede
- Dark Matter (both phases)
Clearing this mode will play the standard credits sequence, capped off with a special illustration showing Kirby wielding the Rainbow Sword with his friends, captioned "EXCELLENT!!"
Kirby's Dream Land 3
Referred to as Boss Butch in-game. The Boss Butch fights feature different backgrounds from the Story Mode. The following bosses must be defeated in order:
- Whispy Woods: takes place in autumn, with Whispy and all the other trees having orange leaves.
- Acro: takes place in the open air rather than a cave.
- Pon & Con: takes place in a volcanic cave with rising ashes.
- Ado: takes place at sunset, with pink clouds.
- King Dedede: takes place at sunset, with pink clouds and rising confetti.
- Dark Matter & Zero: the Hyper Zone now has a yellow sky with red and blue clouds. In the Virtual Console version, the clouds are orange and green instead.
Clearing Boss Butch is required for 100% completion in Kirby's Dream Land 3, and doing so unlocks a unique credits sequence with different illustrations. Holding L, R, and X after defeating Zero will skip the credits and instead display a special illustration: a victorious Kirby standing atop the defeated bosses with the caption "PERFECT!"
If Kirby is defeated, an illustration relating to the boss he lost to is displayed.
Kirby 64: The Crystal Shards
Referred to as Boss Butch (Japanese) / Boss Battles (English) in-game. The following bosses must be defeated in order:
Defeating every boss without taking any damage will display a special "PERFECT!" screen, which shows Kirby wearing a costume made from parts of each boss.
Kirby & The Amazing Mirror
This mode is unlocked once the game is 100% completed. It is not a formal Boss Endurance, however, as Copy Abilities are made available before the fight begins and it has rest areas with recovery items (4 Maxim Tomatoes) in-between battles, like The Arena. Enemies are fought in a random order (except Dark Meta Knight and Dark Mind at the end). Vitality Hearts collected in Story Mode carry over to this mode.
The Boss Endurance consists of the following encounters:
- Mid-Bosses 1: Mr. Flosty, Bonkers, Phan Phan
- Mid-Bosses 2: Waddle Dee (extra HP), Bombar, Box Boxer
- Mid-Bosses 3: Batafire, Boxy, Master Hand
- King Golem
- Mega Titan
- ??? (Dark Meta Knight: 1st)
- Master Hand & Crazy Hand
- Dark Meta Knight (2nd) & Dark Mind
Master is given before Dark Mind. Dark Mind is fought in all three phases without the interludes, and the credits sequence is skipped. Clearing the mode displays an image of Kirby with a trophy, captioned "You're the Champion!"
Kirby: Squeak Squad
While technically referred to as a Boss Endurance, this mode is more similar to The Arena, in that Copy Abilities are made available in Bubbles before the fight begins, and there are breaks with recovery items in-between. Vitality Hearts and Ability Scrolls collected from the Story Mode are effective in this mode as well.
The line-up of bosses are faced on a map screen similar to those of the main story mode stages. Each boss fight is preceded by a room where a recovery item in a bubble can potentially be found.
The following bosses must be defeated in order:
Note that the Dark Nebula fight immediately follows the defeat of Dark Daroach, and includes the chase sequence from the story mode.
A unique peculiarity is that the player can obtain extra lives by mixing bubbles, allowing Kirby to continue if he fails to defeat a boss, rather than having to fight all the bosses again.
Clearing the mode displays an illustration of a victorious Kirby standing atop the defeated bosses with the caption "CONGRATULATIONS!"
Image shown if L+R+X is held after Zero is defeated in Boss Butch