Boss

Every 6 stages, you will encounter a boss nearly the end of the level.

Boss Battles
Mozzkeeper= The Mozzkeeper is the first boss of The One Billion Survivor. He has 2500 HP, and his claws deal 40 to 70 damage. He also has a challenge that you do not have to collect the ice diamonds to kill it. The next boss is Jalsakeeper. Jalsakeeper= The Jalsakeeper is the second boss of the One Billion Survivor. He has 4000 HP, and his claws now deal 150 damage instead of 40 to 70. The previous boss is the Mozzkeeper and the next is RoboRiot. RoboRiot= RoboRiot is a complicated boss and the third one in The One Billion Survivor. He has 5000 HP and throws Cyber-dogs, and has a hose of water. The previous boss is the Jalsakeeper and the next is the Dynamix Master. Dynamix Master= The Dynamix Master is a hard boss and the fourth in The One Billion Survivor. He has 7500 health and has 2 phases. The first phase is very simple, he will shoot fire balls, rockets and electric. The second phase is hard, he can simply clone himself into 10 clones. Initially all 10 clones come down at the same time, but as the master loses health, they come at different times. RB-Dragon 2000= The RB-Dragon 2000 is a very hard boss and the fifth in the One Billion Survivor. He has 10000 health and he has 2 heads. One is in fire, while the other is in ice. The dragon is simply created by OctoDeath by fusing RIO and ROU. Watch out for his spiky back as this will cause heavy damage. Aside from these attacks, the dragon can also slam its six claws twice. Its claws deal 100 damage. Rapid Rave Slayer= The Rapid Rave Slayer is a mini-boss located on stage 6-4, in the One Billion Survivor. He has 12000 health and melee attacks deal 100 damage. He is a death slayer in dark red, and wears a skull head. OctoDeath= The OctoDeath is the one found on stage 5-6 and 6-6 as the sixth boss, in The One Billion Survivor. He has 14000 health and melee attacks deal 180 damage. PartyRiot= The PartyRiot is an upgraded version of RoboRiot, he now hoses fire and ice, as the seventh boss, and this boss has 25000 health, and throws more-harder Cyber-dogs instead of normal Cyber-dogs. Ultra Ground Nation= Ultra Ground Nation is the eighth and final boss, found in versions 2.2 phase 2 and lower. He has the same HP from The Haunted House, Secret of the Ghost Ball: Episode 17: The Malediction Malfunction, (50000 HP), but he is slightly weaker than the Underground Nation. Extra Final Boss= The Extra Final Boss known as The Ultra Demonic Nation or The Ultimate Thronemaster Nation Prime 2 DX when your game's update is version 2.4 or higher, commonly found after beating all 20 Fright Zone Challenges, but he has 40000 times the HP from stage 8-6 (2,000,000,000 HP). It is the extra level, found in Story Mode, and the extra final boss that has the same attacks as the Underground Nation, except he is 1000 times powerful, than the final boss in The Haunted House, Secret of The Ghost Ball: Final Episode: Shinbi Apartment: Doomsday (P2). After beating the last battle, the credits are different. First is The Haunted House: Secret of the Ghost Ball ' s ending, and then Fight and Flight.

The level is initially hidden as a secret to the Fright Zone Packs 1 and 2. Whenever you're trying to access the level without possessing the Golden Powers and Fright Zone Powers will initiate a note. "It's no use, that level is locked. Possess the Golden and Fright Zone Powers to access. Not sure if it's a secret level. It is very crazy."

The Hard Extra Final Boss is included after beating the Glitter Force game created by Hyper Software. This level is eventually also called Stage 8-7 Pro EX. Can you beat the extra final boss?

Trivia

 * As of version 1.05 P1, Hard Mode is removed and replaced by new stages with Hard, Expert and Super Expert. However, it was re-added in version 2.00.0, codenamed, "Extra Story Mode".
 * The Super Expert difficulty is introduced in version 1.06, while Boss Mode is introduced in version 1.7 alongside the Cosmic girls.