The player can also blow bubbles. These can trap enemies, who are defeated if the bubble is then burst by the player's spiny back. The bubbles also float for a time before bursting, and can be jumped on, allowing access to otherwise inaccessible areas. If a bubble containing an enemy is allowed to burst on its own, it turns "angry", becoming pink-colored and faster than normal.
Contact with the enemy is deadly, resulting in the loss of a life.
The objective of each level is to defeat all the enemies.
Each level (or round) consists of one screen. Some screens are completely enclosed, while in others the player can fall through holes at the bottom of the level in order to reappear at the top, or use bubbles to reach the top of the screen even vice versa (see gameplay techniques below).
The levels vary in their layout, as well as the types and numbers of enemies present. Also, the way the bubbles move around the levels varies, so they may converging on a certain point, move at different speeds, or be pulled down as if by gravity, etc., usually with notable effects on a level's difficulty. Also, the length of time before a bubble bursts varies between levels.
Each level (with two exceptions) has a time limit, the length of which varies between levels. If the level is not completed in time, an invincible "Skel" (see below) enemy appears for each player, and all enemies become "angry", with a change in color and increase in speed. The Skel only disappears when the player dies, or if the level is completed by defeating the other enemies.
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.).
There are a variety of enemies that move about in different patterns. As well as killing on contact, some enemies fire missiles that can kill the player. The enemies can sometimes turn "angry", triggered by allowing a bubble containing an enemy to burst on its own, or by failing to complete a level in the time limit. Angry enemies are pink colored and move faster than the normal kind, thus making them more dangerous. 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:
|Uncategorized name||Japanese name||European name||Description||Super mode counterpart||Nonsuper mode counterpart|
|Bubble Buster||Zen-Chan||Benzo||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.||Incendo|
|Stoner||Mighta||Boris||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.||Willy Whistle|
|Beluga||Monsta||Blubba||A flying 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||Hullaballoon|
|Hullaballoon||Pulpul||Boa Boa||An orange 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.||Beluga|
|Coiley||Banebou||Bonnie-bo||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||Hidegons||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.||Bubble Buster|
|Willy Whistle||Drunk||Bonner||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.||Stoner|
|Super Socket||Invader||A silver 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|
|Baron von Blubba||Skel-Monsta||Baron von Blubba||It is the invincible dead version of Beluga 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||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||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 Z+1 monsters will make Z 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.
In Taito's PC port, however, killing Z monsters will cause the Z-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.
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.
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.
Unusually, the arcade version also has two cheat modes built in. By entering certain combinations of movements and button presses on the title screen, these can be activated for the next game to be played.
The first cheat, Original Game, causes the secret treasure rooms on levels 20, 30 and 40 and the warp door on level 50 to appear every time, regardless of whether one of the players is still on their first life. To enter this code, while at the main Bubble Bobble logo screen enter 'Bubble, Jump, Bubble, Jump, Bubble, Jump, Right, 1P Start'. Some text reading 'Original game...' should appear in blue writing at the bottom of the screen.
The second cheat, Power Up!, grants the players the training shoes (for extra speed) and the yellow and blue candy (for rapid-fire and fast moving bubbles, respectively) at all times, making the game significantly easier to play. To enter this code, while at the main Bubble Bobble logo screen enter 'Left, Jump, Left, 1P Start, Left, Bubble, Left, 1P Start'. Some text reading 'Power Up!' should appear in red writing at the bottom of the screen.
The Super Bubble Bobble mode detailed above is also entered in the same way as the cheat codes. To enter this code, while at the main Bubble Bobble logo screen enter '1P Start, Jump, Bubble, Left, Right, Jump, 1P Start, Right'. The game logo should change to include the word 'Super'.
By completing the different endings, the player is given clues in the graphic presented on how to work out the cheats.
The following Initials can be entered when you achieve the highest score, on the next game different bonuses are given. These can be quite significant in value, and usually compose of also waiting on the first screen and not killing all the monsters until the prize on the top right appears.
The (unnamed) "Cave of Monsters" in this version seems to really be an emptied well. To obtain the good ending (to make it fill up with Moon Water) Bub must obtain three "jewels" from fairies he can meet after defeating three bosses (giant versions of Coiley, Stoner and Incendo, none present in the arcade game). Doing this will set free a fourth fairy who will then, thanks to the "jewels", fill the well and revive nature (even though the story of the game didn't mention nature suffering until then). Bub (who returns human), Bob and their parents (who were never transformed) are seen in the ending but their girlfriends never appear in the game.
The revival of nature seems to be suggested also in the Master System port's ending (which otherwise only revolves around the girlfriends' kidnapping, dismissing the parents completely).
The ending is Bub obtaining a bottle of Moon Water, and the screen fades to white and cuts to only a cute still picture of the Bubble Bobble characters (minus Bob).
Some Bubble Bobble ports however, from the date of release of the arcade version up today, have been heavily criticized for their mechanics deviating significantly from the arcade version, adversely affecting the gameplay.
For example, in many versions of the game the two-digit trick to make extra bonuses appear at the end of the stage just doesn't work, or the score and bonus awarding system is entirely different, in part due to the complexity of the original one, and most of the aforementioned techniques can be much harder or impossible to reproduce, thus completely changing (arguably ruining) the gaming experience.
Examples include even comparatively recent versions such as the (1996) PC/PlayStation/Sega Saturn versions by Acclaim: they either have different game mechanics (too fast dropping speed, barely working shoes, bubbles going through walls, different jumping physics and many non-implemented techniques) or different behaviour for some monsters (especially the time-up monster) In some ports, including the TI-83 version, the time-up monster doesn't appear at all.
Another example is the early 1989 PC version by Novalogic, which had the possibility of diagonal jumps with a single keystroke (thus enabling players to go through walls), lacked completely the ability of kissing monsters, and had different rules governing the appearance of some bonuses (most notably the orange-yellow sweet).
The various NES and Game Boy ports and sequels are very different, often featuring scrolling screens, different enemies, and the ability for the dinosaurs to fly.
In general, there are as many variations to the game mechanics as there are versions, with some being more faithful to the arcade version than others and some resulting in noticeably different gameplay experience. Although that is a general rule regarding ports of any game, in Bubble Bobble it can become very noticeable and annoying because of the game relying primarily on its fast paced and trick-filled gameplay.
One of the few versions having game mechanics and gameplay very close to the arcade version is Final Bubble Bobble for the Sega Master System, even though it introduced extra gameplay elements (in particular two new bosses like in the GB version and the need to obtain the content of certain secret rooms to reach the second set of 100 levels and then again to obtain the true ending). Moreover, the version included in Taito Legends for the Xbox, PS2, and PC should be a near-perfect copy of the original arcade version, as it features the original ROM running under emulation. However, even this version lacks accurate emulation of an MCU in the original hardware that handled monster behavior and other things. As of 2007, fully accurate emulation is implemented only in MAME (versions 0.107u3 and up).
Bubble Bobble inspired many sequels, including:
There are a couple of previous Taito games which sort of anticipated the Bubble Bobble legacy because of their inclusion of characteristic common elements or even monsters (e.g. the Mighta and Monsta both appeared first in the game Chack'n Pop, and in fact level 29 of Bubble Bobble is a direct copy of level 1 of Chack'n Pop) :
Bub and Bob also appeared in Puzzle Bobble, otherwise known as Bust a Move in the United States. Bust a Move was followed by many sequels, for many consoles, including PlayStation, Nintendo 64, Game Boy, Game Boy Color, Game Boy Advance, Nintendo GameCube, Wii, Dreamcast, PlayStation 2, Xbox and the N-Gage, along with computer and arcade versions. This spin-off franchise became more popular than Bubble Bobble itself, and has (so far) outlived it.
Some examples of successful non-Taito video games resembling Bubble Bobble in some or even all of the above aspects are:
Ultra Balloon (1996), by SunA Corporation (also manufacturer of Hard Head series), is an evident Bubble Symphony copy and the only Bubble Bobble-inspired arcade game to actually copy the bubble-blowing and popping system.
Bubble Bobble also inspired a few software publishers to publish derivatives of the game for the PC and Mac. Such titles include Bubble Bobble World, Bubble Bobble Quest, Bubble Bobble Nostalgie, Bub & Bob, and The Bub's Brothers. Such games are marketed online.