Bubble Bobble (ƒoƒuƒ‹ƒ{ƒuƒ‹, Baburu Boburu^?) is an arcade game by Taito, first released in 1986. It was ported soon for numerous home computers and game consoles. The game features two Bubble Dragons, Bub (Japanese "Bubblun"), who is green with yellow spikes/horns and Bob (Japanese "Bobblun"), who is blue with cyan spikes/horns. Together, they journey through the Cave of Monsters to rescue their girlfriends. They move over a system of platforms, busting and pushing bubbles, avoiding enemies and collecting a variety of power-ups.

Game mechanics

The main reasons that many computer or game console ports of this game - even when released several years after the original - can seem lacking and incomplete in some aspects is because the original arcade game, despite its apparent simplicity, features some rather complicated and convoluted game mechanics.

Levels

Each level (or round) consists of one screen, with no scrolling or flipping. The dinosaurs can move around the levels by walking on platforms, falling through empty space, jumping through platforms from below and (in some levels) falling through holes at the bottom of the level in order to reappear at the top, or even vice versa (see gameplay techniques below).

Apart from jumping, the characters can blow bubbles. Bubbles also float in from the top or bottom of the screen in many levels. They pop after a certain amount of time, when they hit the dinosaur's spiked back, if they're squashed against a wall or another dinosaur or if they're fallen upon. By holding down the jump button, it's possible to bounce on top of bubbles, which is sometimes necessary to reach platforms. The main objective of the game is to trap enemies in bubbles, and burst them, destroying the enemies. Defeating several monsters at once awards exponentially increasing point awards.

Each round also features invisible air currents and custom bubble physics, causing bubbles to move in predetermined trajectories, such as converging to a certain point, moving very quickly or very slowly, being pulled down as if by gravity, etc., usually with notable effects on a level's difficulty.

Some levels have very short bubble-popping times, meaning that bubbles pop almost as soon as they emerge. This becomes extreme in later levels to the point of only being able to kill monsters by "kissing" them (blowing a bubble in such a way that it's immediately squashed against the dinosaur, causing instant death to an enemy). Time limits are also used to increase the game's difficulty; two rounds having no time limit, some levels are almost impossible to finish under certain conditions (single player, lack of certain bonuses etc.). When the time limit expires, the player does not die instantly, but rather an invincible "Skel" (see below) enemy appears for each player, and all enemies become 'angry', with a change in colour and increase in speed.

There are a variety of enemies that move about in different patterns. Contact with an enemy (or the missiles fired by some) will kill a dinosaur. The dinosaurs' job is to complete the level by killing all enemies in it. If this is not achieved within a time limit, the message "Hurry up!" will flash across the screen. When this happens, enemies become "angry" (making them red and move faster thus making them more dangerous). Approximately ten seconds later, one or two Skel enemies appear on screen. Enemies also become "angry" if they escape from a bubble that is not burst quickly enough by one of the dinosaurs. They may (but do not always) calm down when one of the dinosaurs dies. When in Super Mode, most enemies get swapped with a counterpart, e.g. PulPuls replace Monstas and vice versa.

There are 8 kinds of normal enemies, plus the final boss and two kinds of invincible monsters that appear after the "Hurry up!" limit, each with their own names. Roughly, in order of appearance in the Normal version of the game, they are^[1]:

• Bubble Buster (Japanese "Zen-Chan") (Benzo in Europe): A box-shaped, clockwork walking monster with a medium moving speed and good jumping abilities. He's the first monster that appears in the game at stage 1. Interestingly, this monster also appears in the graphic tiles of the ROM of the arcade game Chack'n Pop, along with the Stoner and Beluga, but doesn't actually appear inside the game. Super Mode counterpart: Incendo.
• Stoner (Japanese "Mighta") (Boris in Europe): A walking monster with red eyes who wears a white robe, much like a ghost. Has a medium moving speed, good jumping abilities and is able to shoot. First appearing in this game at stage 6, this monster actually first appeared in Taito's 1983 game Chack'n Pop. Super Mode counterpart: Willy Whistle.
• Beluga (Japanese "Monsta") (Blubba in Europe): A flying blue/dark purple monster shaped roughly like a small whale. It flies fast but can only bounce off walls to change direction. First appearing in this game at stage 10, this monster actually first appeared in Chack'n Pop. Super Mode counterpart: Hullaballoon.
• Hullaballoon (Japanese "Pulpul") (Boa Boa in Europe): A pink flying monster looking like a toy bear with a small rotor on his head. Flies around slowly but with greater control than the Beluga, and creeps in very small openings that other monsters and players cannot pass through, thus making it very dangerous in some rounds. It makes its debut at stage 20. (Super Mode counterpart of Beluga)
• Coiley (Japanese "Banebou") (Bonnie-bo in Europe): A mushroom shaped-monster which can only move by making short jumps, having a single powerful spring instead of legs. It makes its first appearance at stage 30, and is the only monster who stays the same in Super Mode (he is not swapped with any other monster).
• Incendo (Japanese "Hidegons", singular): A fast walking monster with shooting abilities, but poor jumping. Unlike the Stoner, he doesn't have to stop walking in order to shoot fireballs. He makes his first appearance at stage 40. (Super Mode counterpart of Bubble Buster)
• Willy Whistle (Japanese "Drunk") (Bonner in Europe): A fast moving monster with good jumping capabilities, and able to throw a bottle which rebounds off walls and is re-caught by the thrower. He first appears at stage 50. The final boss is modelled after them, but is instead called Grumple Gromit or Super Drunk. (Super Mode counterpart of Stoner)
• Super Socket (Japanese "Invader"): A robotic-looking monster, which behaves similarly to the enemies from the computer game, Space Invaders. Can only move left or right, and falls if it reaches the end of a platform. Shoots lasers downwards. It first appears in stage 49, but became infamous for stage 57 for the NES console. Although, it does not appear at all in the Super version of the game. (Incendo takes its place in Super Mode.)
• Baron von Blubba (Japanese "Skel-Monsta"): It is the invincible monster that appears after the time limit for a round has expired (this limit can be as low as 1 or 2 seconds on some rounds, but there are two rounds with no time limit: round 94 and round 100). Baron von Blubba looks similar to a white Monsta, but can only move vertically or horizontally at timed intervals. It can pass through walls, ceilings and floors, and speeds up until either the level is completed or a player is killed. In two-player mode, two of them appear, each homing in on a particular player, although either player can be killed by touching either of the Barons. Baron von Blubba can also be dismissed by touching a player who has just been killed and is still flickering, and thus invincible. Another way to get rid of it is to pick up the flashing heart powerup (the only one that remains on the screen after the "Hurry up!" warning).
• Rubblen^[2] (Japanese "Rascal") appears in the secret diamond-filled rounds, which can be accessed by special bonuses that appear on rounds 20, 30 and 40 under certain conditions (explained in later section). Rubblen functions much like Baron von Blubba ("Skel-Monsta"); To trigger his presence, the player must remain idle for approximately 10 seconds. At this time, Rubblen will form and separate himself from the stone structure in the center of the room. Once he has been triggered, Rubblen will trail the player until he or she exits the area or gets hit. If the player receives a Game Over within a Secret Room, the maximum "reached round" on the high score screen will be noted as "Round 102" (for Level 20's Secret Room), "Round 103" (for Level 30's), or "Round 104" (for Level 40's); when a New Game is started after this Game Over, the player will be warped from Level 1 to the secret room he or she died on.
• Grumple Gromit (Japanese "Super Drunk") is the end-game boss that appears in level 100. It is large, bounces off walls, and fires arcs of bottles. The level contains a magic potion that allows the players to breathe lightning bubbles. It becomes trapped in a bubble only after being struck by many lightning bolts. In Super Mode, the last boss is not the real Gromit, but Bub and Bob's parents who were turned into it by a mysterious villain (whose identity is revealed in Rainbow Islands). Before regaining their true forms, they change into a large bubble dinosaur (which is what ties them to said mysterious villain)

A relatively unknown and obscure part of Bubble Bobble gameplay has always been the way the various bonuses appear. While most of them may appear completely random, the game actually keeps a series of internal (and unseen) counters about events such as number of jumps, jumps over bubbles, bubble bursts, bubbles blown etc. during a round or in the whole game, maximum number of monsters blown in a certain round etc. and these events are actually used to determine which bonuses will appear, and to a certain extent when they will appear.

Virtually the entire game is controlled in this way, appearing to be random but actually able to be manipulated by the player should he or she know how. The only item that is known to be completely random is the "fireball bubble" that appears very occasionally, a red bubble with a flashing yellow spark inside it that gives the players fireballs for the next five levels. This is generated with a chance of 1 in 4096 each time a bubble drifts into the level from the top or bottom of the screen.

Some known events and the effect they have on bonuses are:

The number of distinct EXTEND bubbles that will appear on a round depend on the maximum number of monsters killed during the round, or on a previous round if said previous round didn't have "openings" for EXTEND bubbles to fly in, or was completed before they could appear. In general, killing N+1 monsters will make N distinct EXTEND bubbles appear. Since the game actually can have only 7 monsters per round, killing 7 monsters in a single bubble cluster will make all 6 EXTEND letters appear. Spell EXTEND to clear the stage you are on and gain an extra life. ^[3]

In Taito's PC port, however, killing N monsters will cause the N-th letter of the word to appear — making the N extremely hard to get because there's only few levels where you can easily pop five enemies simultaneously. This is probably a bug.

Another known event-triggered event is the appearance of candy cane bonuses: if a player rides a bubble more than 20 times, then a candy cane will surely appear in that round.

Other bonuses can be made to appear in similar manners, and there is at least one internet page listing some of the events and their effects [1].

For a special bonus on the NES version, a player must enter the password HIJID, select 2 player continue, and finish round FO (last level) with both players alive. After the entire ending has run and the player is prompted to press start, the player will receive a reward. The reward is a sound test for the whole game.

[edit] True Ending

The arcade original has several different ways in which the game can be finished. Completing the final round when playing in single-player mode, the game displays a message stating that the player hasn't reached the "true ending." The player is then warped back to a random level between 50 and 95 and carries on playing. In this way, a skilled player can make a single game last for a very long time.

Finishing round 100 with both players active displays the "happy ending," in which both of the players' girlfriends are rescued. But a cryptic message then appears stating that this is also not the "true ending", and displays a code that must be entered into the game at the title screen.

Entering the code changes the game logo to read Super Bubble Bobble, and the next game that is played has all the enemies switched around, making for a much more difficult game. Finishing the game with both players active in Super mode finally reveals the true ending of the game.