- or : Use the joystick or console control pad to direct the movements of Bubblun and Bobblun. Press left or right to make the dinos run in either direction. Up or down have no use in-game; although depending upon the system, they may be used to navigate menu selections. Note: In some of the early home computer versions where only one fire button was available, jumps can be performed by pressing up on the joystick.
- (Bubble): Press the first action button to make your dino spit bubbles. The speed, rate, and distance of the bubbles can be improved by collecting items throughout the game.
- (Jump): Press the second action button to make your dino jump up. Jumping can be performed in conjunction with moving. Your dino will jump the same height no matter how long you press the jump button for. Note that it is possible to make your dino jump on top of bubbles without popping them by holding the jump button down.
Bubblun and Bobblun
Meet Bubblin and Bobblun, the two dinosaurs which players control throughout their exploration of the Cave of Monsters. Bubblun and Bobblun are no ordinary dinos. They have two special abilities that set them apart: they can jump very high, and they can spit bubbles. The bubbles that they spit are capable of encasing and capturing enemies shortly after they've been fired. Once the bubbles begin to rise on their own accord however, they are no longer capable of catching enemies. Once caught, the enemy will struggle helplessly inside the bubble for a period time until one of two things happen. Either the bubble is burst by one of the dinos, killing the enemy, or the enemy becomes enraged and the bubble weakens, permitting the enemy to safely escape the bubble. Bubbles may be burst by landing on top of them and crushing them, or jumping beneath them and popping them with your dino spikes. Players advance to the next round once all monsters have been popped and/or eliminated from the stage.
Bubblun and Bobblun are vulnerable to the touch of the various enemies and the projectiles that some of them fire. They lose one life every time they are hit. The game is over when all of the dinos' lives are lost. Extra lives are granted throughout the game at regular point intervals and through other means. The dinos can safely collect the various items that appear throughout the stages by touching them. Some bestow various powers and bonuses.
Bubble Bobble can be enjoyed simply by blowing bubbles, capturing enemies, and popping them to advance to the next level. However, in order to clear the more advanced levels, players must familiarize themselves with a couple of techniques that expand upon the basic gameplay principals. Below are a collection of the most important techniques to know. Mastering them will enable players to reach higher and higher rounds and get closer to the ending.
- Kissing monsters or just kissing means killing a monster by blowing a bubble at almost contact distance: the monster will be instantly bubbled and the bubble will be instantly popped, giving the visual effect of the player killing a monster with a "kiss". Some players flip their joysticks in the opposite direction after pressing the bubble buttons, giving more chances of an "instant pop" and changing flight direction for the dead monster. This technique is useful in stages where monsters move too fast, bubbles last for too short a time or it's otherwise hard to bubble them normally. Of course good timing is required for this technique to work.
- Riding bubbles means keeping the jump button pressed when dropping on a bubble: if done properly, your dino will instead jump on it instead of popping it, enabling him to "ride" bubbles and reach otherwise unreachable areas. Some stages can't be finished without this technique.
- Climbing is a step up from riding bubbles. It means standing at half a bubble distance from a wall, jumping and blowing a bubble almost simultaneously, jumping up from that bubble and blowing another bubble and so on. This is necessary if the air current pushes down bubbles but you need to climb up. Having the rapid-bubbling power-up (the yellow candy) makes climbing a lot easier, especially if you have also collected the running shoes.
- Bubbling oneself through means "riding a bubble" through the opening at the top of a stage or even just through the ceiling of a stage in order to appear at the lower part, like some flying monsters can do. This technique is required to finish some stages or to get unstuck from some places, or just to save time.
- Blowing against the wall means blowing bubbles against wall at contact distance: the bubbles will pop immediately thus giving the player 10 points per bubble pop. This can be used to either increase a player's score, or to set a player's score to a specific amount, in order to do other tricks.
- Two equal digits means using the "blowing against the wall" technique or other score-adjusting techniques in order to make the two penultimate (100s and 10s places) digits of at least one player equal, e.g., 456770, before the last enemy bubble is burst. If done correctly and the score is not modified when this occurs, then all remaining non-special bubbles on screen will be turned to 700-point bonuses, whose appearance depends on the digit picked. E.g., 7 gives Chocolate Ice Creams, 3 gives Hamburgers, and so on.
- This trick is easier to do with two players (one player adjusts his score and the other bursts the bubbles), but it can also be done with only one player, although calculating exactly how much (and if) one's score will be modified when bursting the last enemy bubbles can be extremely complex, if not unpredictable, especially if there are very large and clustered bubble bunches.
- Rounds with numbers ending with 5 and 0 up to and including level 50 generate bonuses from bubbles automatically. Other occasional rounds (including round 1) do it as well.
In many stages that contain openings on the bottom, bubbles will continuously float on to the screen. While some of these bubbles are regular ordinary bubbles, some bubbles will instead possess special properties. You can tell which properties these bubbles possess just by looking at them. Typically, when these bubbles present themselves, they are helpful or even integral to the solution of the stage.
Extra lives may be earned by reaching particular scores. In the arcade, this is set by default to 30,000, 100,000, and 400,000, but may be adjusted by the arcade operator. However, it is possible to earn extra lives at any point in the game by collecting the six E-X-T-E-N-D bubbles. These are bubbles with the letters D, E, N, T, and X printed on them. There are actually two distinct E bubbles, each with their own color. A tally of the distinct bubbles you have popped is shown on the respective player's side of the screen; left for Player 1, and right for Player 2. When a player pops a complete collection of all six bubbles to spell out the word "EXTEND", gameplay is interrupted and the player is treated to a cinematic of their dino popping six giant EXTEND bubbles, ultimately rewarding the player with one extra life. Then game play resumes with the players automatically advancing to the next stage. The player who was awarded the extra life continues with an empty tally.
The method to make these E-X-T-E-N-D bubbles appear is as follows. Any time you pop three or more bubbles containing enemies simultaneous (that is, they are destroyed with one single popping effort), the game will provide one less E-X-T-E-N-D bubbles than the number of enemies popped. Therefore, if you pop five enemies simultaneously, four E-X-T-E-N-D bubbles will be queued. These bubbles will only appear in rooms that have shafts which connect the top and bottom of the screen. If these shafts are not present, or the last enemy is killed before these bubbles appear, they will appear in the next stage containing shafts. Which bubbles appear is entirely random. Therefore, it is possible to get identical copies of the same bubbles.
There is no reward for collecting a bubble that is already present in your tally. However, collecting three of each particular bubble will result in a Staff being generated as the next stage's special item. Each E-X-T-E-N-D bubble may only be collected by one player, and the benefit only applies to the player who collects all six distinct bubbles. The player who did not receive the extra life keeps their existing tally of bubbles.