When Bubble Bobble was ported to the Sega Master System, several elements were added that were not present in the original game. These included more secret rooms, more cinematic endings, new special items, two new boss fights, and the lack of a Super Mode (The original levels with enemies replaced were presented unlocked after defeating Grumple Grommit).
The first new boss is a giant Stoner. It walks around the room, throwing a deluge of boulders down on Bub and Bob. A Cross of Fire is positioned at the top of the stage, which Bub and Bob must collect to defeat the Stoner. If Bub and Bob run out of fireballs, a new cross will appear for them to collect. After being hit enough times, the Stoner is trapped inside a bubble, which Bub and Bob can pop to complete the level.
The second boss is a giant Incendo. It bounces across the room and releases fireballs. Two statues sit at the top of the stage, which Bub and Bob can collect to increase their stats and gain the ability to shoot Lightning Bubbles. After being hit enough, the Incendo is trapped inside a bubble, which the Bub and Bob can pop to defeat it.
Previously featured in Rainbow Islands, the Peacock Feather summons a fairy that circles around Bub and Bob. If it makes contact with an enemy, it will defeat the enemy on impact. The fairy lasts for three stages.
The Book of Ice freezes every enemy on screen inside a cube of ice. Collecting the cubes gives Bub and Bob 10,000 points each.
The Chalice creates a black hole in the center of the level that absorbs every enemy on screen. On stage 155, the black hole is used as an entrance to a Secret Room.
There are three crystal orbs that Bub and Bob must collect to unlock the True Ending. Each one appears in a Secret Room, which can be unlocked under different circumstances.
The Magic Key unlocks Secret Rooms that appear later in the game. It is collected in a Secret Room on level 115.
The mirrors must be collected to unlock the True Ending. They are found in Secret Rooms which are unlocked by obtaining the Magic Key.