Each level (or round) consists of a single screen which is entirely visible. All levels are composed of platforms which are arranged in various patterns or images. Every level contains two walls on the left and right side of each stage which confine the characters. However, many levels contain openings on the top and bottom of the stage. Characters who fall through the bottom of the stage will reappear at the top and continue to fall down. Each level contains several aspects that change from one round to the next.
- Monsters and bubbles: Each stage has its own composition of enemies which will appear when the stage begins. In most cases, the enemies appear immediately at the start of the level. However, in some cases, enemies do not appear all at once, with some being delayed. Some levels release a mixture of special bubbles, including water, lightning or fire, which are intended to be used to complete the stage.
- Monster and bubble speed: As the levels go by, the speed of the game slowly increases. The speed at which the monsters move about the stage will increase, as well as the speed at which the bubbles float around the stage. Additionally, the rate at which the enemies can burst free from the bubbles changes from stage to stage. It can change more drastically than other speeds, causing some stages to allow enemies to escape very quickly, followed by stages where it takes the enemies longer to escape.
- Time limits: In the original arcade version, stages have different time limits. After a period of time, the "Hurry Up!" message will appear, warning the player(s) that the Skel-Monster is about to appear. Some period after, typically 10 seconds, but not always, the Skel-Monster will begin to hunt down the player(s). The speed at which "Hurry Up!" appears varies, but tends to increase as the levels increase.
- Air flow: When bubbles are blown on to the screen, they will follow air currents that determine which way the bubbles will move. By default, most bubbles simply move up to the ceiling, but in certain stages, they may move left or right, or even be blown down. In many stages, there is a final point where the bubbles amass, although this is not the case all the time.
- Item position: In each and every stage, at least one, possibly two items will appear at predetermined positions. After seven seconds into the stage (or four if you collect the crystal ball), a point item will appear, based on how fast you completed the previous stage. After 12 seconds (or sooner if you collect the crystal ball), a special item will appear provided you fulfilled enough requirements to make one appear. If you fulfilled more than one requirement, the item which appears is typically the item which required the "higher" number.
Finishing the Game
First you have to survive till level 100. Take the lightning potion and hit the bad guy with 100 lightning bolts. His pattern is easy to follow and very predictable, just avoid his projectiles. He'll end up in a big bubble, pop him for 1,000,000 points! You've found love and friendship! If you finish the game with only one player then you are told that it is not a true ending and you should "Never forget your friend!"; you are sent back into the game to "try again!!". Even if you finish the game like this with two players, you get a good ending which is still not the best ending.
In order to get the best ending, you must play in "Super" mode; that is when you input the title screen cheat which makes the cloud read "Super Bubble Bobble", not just "Bubble Bobble". Monsters will be swapped with their Super-Mode counterparts. If you beat all 100 levels of Super mode, and beat the boss with two players, you get the "True and Happy ending".
Bubble Bobble allows continues to be used when a player runs out of lives. While most arcade games display a continue timer before returning to the title screen, Bubble Bobble ends immediately once there are no players in the game.
A single player can cover for the other player returning to the game. However, a lack of second player requires a credit within the machine, as well as holding down the start button just before the game ends.