An arcade game in which mini-dragons Bub and Bob go on a 100-level quest to get their girl-dragons back. Each level is a single-screen affair, in which you must dispose of all the monsters on the level all the while picking up goodies and scoring points. If you touch a monster, you die, lose a life, and reappear having lost any power-ups collected. To dispose of monsters, you shoot bubbles at them. The monsters get trapped in the bubbles, which you must then pop with your feet, head, or dorsal spines. The disabled monster then flies up in the air and lands on the ground, turning into a piece of fruit or other goody which you may pick up for points. The more monsters you pop at a time, the more points you get, and the better the goodies which appear. If you leave the monster in the bubble for too long, he'll bust out and become angry. Angry monsters move much faster than in their peaceful state. If you take too long to complete the level, all the monsters will become angry, and the game will tell you to "hurry up!" After another short interval of time, an unkillable ghost-monster will appear, and start seeking you. He doesn't go away until you finish the level or he gets you. Hurry up, Bub!

At the end of the level, all the remaining bubbles may turn into goodies! This occurs on level 1, any level whose number is divisible by five, or on any level, if after you dispose of the last monster, the second and third digits of your score (from the right, so tens and hundreds) are the same.

Special bubbles sometimes float up from the bottom of the screen, holding letters in them. If you pop one of each type of these bubbles, you spell E-X-T-E-N-D, ending the current level and giving you an extra life.

Other special bubbles are fire bubbles, water bubbles, and lightning bubbles. Different special bubbles appear on different levels. The fire bubble drops a fireball, which creates a flaming area on the ground where it hits. This fire will kill any monster that touches it, the monster flying up and turning into a red gem. It will also slow down Bub and Bob if they try to move through it. The water bubbles starts a cascade of water which flows down to the bottom of the level. Bub and Bob can ride on this waterfall, and the water will kill monsters, turning them into blue gems. The lightning bubble, when popped, sends a lightning bolt horizontally across the level, in the opposite direction that the player who popped it is facing. Monsters hit by the bolt are killed and turn into yellow gems. If hit, Bub and Bob are stunned by the bolt, and can't move as it passes through them.

If a player makes it to level twenty, thirty, or forty without dying, a gate will appear. If the player enters the gate, it ends the current level and goes to a secret level with a bunch of gems to pick up for points. The secret levels take the place of levels 21, 31, and 41 respectively. In the background of the secret levels, there is some text in strange characters. The text is actually a simple substitution cipher. When translated, the text tells you the secret cheat, er, "helper" codes.

If a player makes it to level fifty without dying, a gate appears which will take the player to level seventy.

The cheat codes must be entered before the player inserts a coin, when the game is showing the title screen. (the one that says "Bubble Bobble" on it) If entered correctly, red text will appear on the lower left of the screen saying the code entered. The power-up cheat is: Left, jump, left, 1UP, left, bubble, left, 1UP. It gives you shoes and all the flavors of bubbles gum, permanently.

Items you can pick up include:

Shoes. Shoes make you move faster.
Bubble gum. There are three flavors. One increases the speed of your bubbles, one makes you shoot them farther, and one increases your bubble-shooting rate.
Umbrella. Grabbing the umbrella will skip you forward some levels. I think it's three levels for an orange umbrella, and five for a red one.
Candy Cane. Getting the candy cane ensures that all bubbles will turn to treats at the end of the level, as well as dropping a giant treat in the middle of the screen worth ten, twenty, or thirty-thousand points. The color of the candy cane determines the kind of treat.
Ring. After picking up the ring, you get points for a certain kind of action. Blue ring gives you points for moving. Purple ring gives you a five hundred points for each jump, and red ring gives you a hundred points for blowing a bubble.
Potion. Grabbing the potion makes all the enemies on the level disappear, filling the empty space in the level with a kind of object, like rainbows, or clovers, a different object depending on the color of the potion. A timer starts, and you must try to get all the objects on the level. If you do, you get a large point bonus.
Cross. There are three crosses, the water cross, the fire cross, and the lightning cross. The water cross fills the level with water, killing all monsters. (The same gems appear for monsters killed with crosses and with the special fire, water, and lightning bubbles.) The lightning cross makes a giant lighting bolt repeatedly strike through the level from top to bottom. The fire cross makes the player shoot fireballs instead of bubbles. This wears off after a large number of shots.
Bomb. The bomb expolodes, getting rid of all the monsters on the level. As a side effect, the players can't blow bubbles, but they can run around picking up treats and opening and closing their mouths.
Bell. The bell stays with you until the next time you die.
When you enter a new level, if there is a power item (Cross, bomb, etc) that will appear on the level, the bell will ring.

There are more items, but I leave it to the enterprising player to discover them all.

In addition to the arcade game, there is an NES version of Bubble Bobble which contains much of the same bubbly goodness. Sequels to Bubble Bobble were made, but were not quite the same as the original. The first sequel was Bubble Bobble Part Two, which had better graphics but tweaked the gameplay for the worse, adding minibosses every five levels, and changing the size of the characters, making the levels seem smaller. Another sequel was Rainbow Island, which had neither Bub, Bob, nor bubbles, and Parasol Stars, which followed the path of Rainbow Island.

A successful Bubble Bobble spinoff series is Bust A Move (Puzzle Bobble in Japan), a puzzle-style game in the genre of Puzzle Fighter and others. While it's a different kind of game, it does contain Bub and Bob and lots of bubbles. There have been various Bust A Move games for different platforms, and they are quite fun and addictive as well.

In conclusion, Bubble Bobble is one of the greatest arcade games ever made. It's jam-packed with neat items, it's kinda cute and non-violent, at a time when the easiest game to make was a side-scrolling shooter, and the gameplay is wonderfully fun. If you need any more convincing, just reconsider the fact the the cheat codes are written in ciphers on secret levels that can be gotten to by careful play. Magnifique!

Sources: none. I wrote this up from memory just for fun. Consult a FAQ for a more exhaustive treatment.