Exploring the secret depths of Bubble Bobble's design

Taito's bubble-popping classic holds a number of secrets, and in this guide an expert will show you how to find one that unlocks the game's hidden language and showcases a new dimension of its design.

Secrets can tell you a lot about how a game was designed, and Taito's classic Bubble Bobble is full of them.

Today we're off on a trip to visit one of the least-seen, a secret room that shows up if you get to level 20 without dying. I've been there several times, and I'll show you how you can reach it too, and fairly! But I'm getting ahead of myself, let's introduce the game first….

Taito's popular 1986 arcade game Bubble Bobble is one of a class of game that we might call SRPPs: Single Room Platformer-Puzzle games. These are a category of game that consists of a series of single side-view rooms, where the player controls some small surrogate on the screen, and must typically use a basic set of abilities, often just jumping and a means of attacking, to defeat all of the enemies in the playfield-like room, which then allows passage to the next room, among some large number of them.

Although Donkey Kong itself fits the description if taken literally, SRPPs are actually a fairly exclusive genre. Taito made a few of them, some of them sequels to Bubble Bobble itself; others of the same type are Bubble Bobble's predecessor Chak'n Pop, contemporary The Fairyland Story and Toaplan's 1990 release Snow Bros.

Of them all, Bubble Bobble is the best known, so popular as to be almost legendary. Its popularity is a result of its shallow difficulty curve, its insanely catchy music, its easy-to-grasp gameplay, its vast number of power-up items, and the game's ridiculous depths as far as secrets go.

One of the secrets is the purpose behind this article: there are a set of three secret rooms that become available to players (up to two can play at once) if they can reach rounds 20, 30 and 40 (out of 100) without losing a life.

These rooms are (assuming you weren't spoiled) one of the keys to finding the game's "true" and "Happy End" ending, for reasons we'll get into, but reaching even level 20 without dying at all is quite challenging. This guide is here to help you achieve this feat on your own, and understand how the dev team's decision to implement these secrets adds a new dimension to the game's design.

The Bubble Bobble series

In addition to the original game, there are at least three intersecting and crossed-over series connected with Bubble Bobble that interested devs and players might wish to examine. There's the original sequence themselves, which could be taken to include Rainbow Islands (arcade and ports) and Parasol Stars (various console and microcomputer versions, but no arcade release). Bubble Bobble might also be seen to be a follow-up to the earlier arcade game Chak'n Pop. All of these games are SSRP-type games (except maybe Rainbow Islands), although some of them have some amount of scrolling within their rooms.

Even if they're in a similar genre, these games still play differently enough to Bubble Bobble that there was demand for more games with Bubble Bobble's specific play mechanics. That would bring us the rare Famicom/NES game Bubble Bobble Part 2 (1993) and arcade games Bubble Symphony and Bubble Memories.

On top of these, there's also the Puzzle Bobble side-series, also known as Bust-A-Move, which have completely different play style but use many of the same characters.

Bubble Bobble basics

The game consists of 100 rooms of enemies that can be tackled either by one player going solo, or two playing cooperatively. Each room has different enemies and a different layout. Every room is a single screen. While the game is a platformer, unlike most of them, a player character falling off the screen doesn't immediately lose a life, but instead wraps around to the top. It's very easy to die in Bubble Bobble, so even small advantages should be appreciated.

The player's representatives in the game world are "bubble dragons," color-coded green or blue depending on player. A bubble dragon's a cute li'l lump of scales that can jump about four blocks high (blocks here are much smaller than those in Mario, mind you), with very little control over your motion when you're in the air. You can adjust your motion slightly while in mid-air, but there's still not much you can do once you've launched yourself.

Zen-Chan (aka "Bubble Buster")

Walks left and right, jumps straight up, sometimes takes a running jump to the side.

Monsta ("Beluga")

Moves diagonally, bouncing off of solid objects. Fairly predictable.

Mighta ("Stoner")

Moves as Zen-Chan, but also fires large, round rocks at players on the same line.

Pulpul ("Hellaballoon")

Flies left and right quickly, while slowly moving up or down. A little harder to handle than Monsta.

A lot of deaths come from when you take a leap, and an enemy hits you before you land. In fact, a lot of deaths happen, period. Our favored soaplizards are fragile like, well, bubbles. If any enemy so much as brushes against one of them, they perish on the spot. Bubble Bobble is not sparse with extra lives, at least at first, but it's not long where you're losing them all over the place, and then the game is over.

Continues are odd—you are free to join or continue a game at any time so long as the other player is still playing. If you're in a single-player game, then your game ends the moment you lose your last life, but in a two-player game continuing is easy so long as both players don't run out of lives at once. Unlike as you might be expecting, adding another credit does not allow a running player to simply buy extra lives. This adds a bit of strategy; to get far, the players must be desperate not to run out of lives at the same time. It can help to keep credits in the machine for the event that one player fails early; then they can at least pound on the start button to try to rejoin before their partner also fails out.

It's not just enemies that are problems for our reptile heroes. Bubble Bubble's levels have some places where, if a player enters them, it is basically impossible to escape. One of the earliest such places is Level 19, which has a number of tall shafts with ground at the bottom, far too far for a player dinosaur to leap from. There are a lot of these places where a player can get out by blowing bubbles then jumping on them, holding the jump button down and thus bouncing on them over and over. If that's not possible (the case if the shaft is two blocks wide, as the bubbles have nowhere to go), sometimes a player can get out by popping a passing Water Bubble, letting the flow carry them out of the trap.

If none of these options will suffice, the player must either try to somehow defeat the remaining enemies from their trap (usually using passing elemental bubbles) or wait for the Skel. The Skel, aka "Skel Monsta," aka "Baron Von Blubba," is a skeletal white whale that appears if the players take too long to complete a level. It is an example of what I call a baiter, after Defender's harassing enemy, a powerful, sometimes invulnerable, foe that arrives if the player stalls the game for too long. The Skel is easy to avoid if the player has full movement, at least at first, but it homes in on the players faster and faster until it kills one of them. In a two player game each gets their own Skel. At least, in the process of losing a life, the player is freed from their trap.

However, this is not acceptable for us on our audacious quest. For we are bubble dragons on a mission: to lay our eyes on one of the game's fabled Secret Rounds, and behold for ourselves the wonders contained therein.

Secrets upon secrets

Bubble Bobble's reputation is not built off of its easy-to-grasp gameplay alone. A lot of it, maybe most, comes from the insane array of awesome items and secrets buried in the game. Bubble Bobble's cute facade hides a true player's game, an experience that must be studied and practiced to master, and even then, there's a lot of studying and practicing to do.

About those items. It's usually not far into Bubble Bobble (maybe as early as the first level) where one of the game's many entertaining special items show up. There's the Blue Cross, for instance, which immediately floods the whole board with water and instantly defeats all the enemies, turning them into valuable diamonds. The various Cane items create a gigantic, high-scoring bonus item that appears in the center of the board once the last enemy has been defeated.

Then there are three different flavors of candy, each of which provides a useful powerup that lasts for the rest of the current life. There's powerful weapons, invincibility hearts, time stop clocks, bonus rounds and many other wonderful prizes to discover. There's even an item (the Bell) that alerts you if other powerful items are due to arrive soon. The best of them all may be the Umbrella, which outright skips you forward from three to seven levels.

These special items are quite powerful, and Bubble Bobble is hard enough that figuring them out is an important step towards learning to play it well. We'll be getting to that shortly, but in the meantime I should explain what the Secret Rounds are.

When you reach levels 20, 30 and 40, if at least one player in the game managed to get there without losing a life, its entrance is actually presented as one of these secret items; it just has the graphics of a silver doorway instead of some random treasure. If a player manages to make it to level 50 without dying, the prize is a golden door that skips 20 levels, but good luck finding that one.

Preparatory work

First things first. If you're playing this in an emulator, go into the machine settings and set it to Easy. There's no reason to make this harder than it has to be. Bubble Bobble has a dynamic difficulty feature that increases the difficulty when you gain a life, and decreases it when you die, that can play a major role in your progress. This means, even if you start the game on Easy settings, after a while it'll creep up towards high difficulty anyway. High dynamic game difficulty both increases enemy speed and reduces the time enemies stay trapped in bubbles before breaking out.

Since your aim is to get as far as you can without dying, this means it's actually a good idea to avoid extra lives. These have two sources: points and EXTEND bubbles. If you're serious about getting there by any means, you might want to disable extra lives by points in operator settings.

The first few rounds are easy, especially in an arcade where you're very likely to find powerful items in the first few levels. On a freshly initialized MAME setup this never happens, but in the meantime you'll have to clear these boring early boards yourself. Take advantage of the downtime by launching a lot of unnecessary bubbles and jumping a lot. Why? Well....

Nearly every round in Bubble Bobble generates two items, a points item that appears first (usually 7 seconds in), the value of which depends on how long it took you to finish the previous level, and a special item (at 12 seconds) that give you some kind of ability. There's a tremendous variety of these, and they give Bubble Bobble a lot of its appeal. What's not well-known is the fact that, despite appearances, they aren't random at all.

Every special item has a trigger condition, something you've done in the game up to that point that makes it appear. Internally, Bubble Bobble maintains a large array of counters, and is constantly watching, recording everything you do in a game like a Z80-powered NSA agent. At the start of every level, the game looks through its list and stops when it finds the first counter that's exceeded a specific target value. This target value is usually unchanging, but for some items depends on the game's operator-set difficulty level.

When the machine finds a count that's gone over its threshold, it resets that counter to zero and sets a specific special item to appear on that level. It only does this once per level; any other counters that have been passed continue to grow. There is a set order in which the threshold values are checked, usually prioritizing the more exotic and powerful items, whose triggers are difficult to activate. It also does this regardless of whether the item actually appears or not; if you finish the level before it shows up, it's lost.

The thing about all those counters is, they are not reset at the start of a game! Any progress the previous game made towards generating special items is retained, meaning successive games can take advantage of them to improving their own state. This is what makes playing via MAME a bit more boring than on a physical arcade machine; when an emulated MAME machine starts up, all the counters are initialized at zero, meaning that the first level, instead of possibly generating an awesome item like a Lamp or an Umbrella, will see no special item generated at all!

(As a personal aside, I love it when communal game systems like arcade machines use the actions of past games to influence succeeding ones. Usually, one expects a video game to begin from a zero state every time it is played, but this isn't always the case! Pinball machines sometimes have what are called progressive jackpots that make this kind of thing more visible.)

But one thing that is true of an initialized MAME game is that the Candy and Shoe items, which provide basic but life-lasting powers like rapid fire, fast bubbles, long range and quick movement, but which appear late in the threshold list and this often get overruled by flashy yet temporary powers, have a better chance of showing up. You can trigger them yourself, and should take advantage of the early rounds by building them up. Pink Candy (long range) appear after players fire 51 bubbles; Orange Candy (rapid fire) appears after players jump 51 times; Blue Candy (fast shots) appears after players directly pop 51 bubbles; and the fast-movement Shoe counts the number of frames that players have collectively spent moving along the ground. If you're efficient about building up your counters, you can have all four of these powers active by the end of Round 5.

Pink Candy: Long Range

Triggers when you fire 51 bubbles

Orange Candy: Rapid Fire

Triggers when you jump 51 times

Blue Candy: Fast Shot

Triggers when you pop 51 bubbles

Shoe: Extra Speed

Triggers when you run a sufficient distance on the ground

There are two other items of special interest to us. The Magic Potion items, when collected, immediately cease the current round and turn it into a bonus round, filled with points to collect, but more importantly immediately defeat all the enemies upon collecting it.

There's a number of other items that instantly finish a round for us, but most of them have special requirements, like popping a lot of Fire bubbles, collecting a lot of items or killing enemies with different elemental bubbles. Potions are special because their requirement can be done on many levels.

Their trigger counter follows the number of times either player wraps around the screen from bottom to top. Do this at least 15 times and a potion will appear in an upcoming round. You can do this quickly by finding a place where a bubble floats near the top of the screen and bouncing on it repeatedly, causing your lizard-guy to bounce up off-screen, or else finding one of the rare levels where there's a step from which you can naturally jump high enough to wrap the screen.

Of even greater importance are the Umbrella items. These items instantly advance you ahead up to seven levels, and you still get credit for the levels you passed as if you cleared them. If you could somehow make Umbrellas appear at will the Secret Rounds would be easy to reach, but their appearance is limited by the fact that their trigger condition counts popped Water Bubbles, which do not appear in most rounds, and appear slowly when they do. 15 Water Bubbles popped (whether they release water or not) will cause the weakest Umbrella, that skips three levels, to appear.

To get the five-level skip Umbrella, you must have a total of 20 Water Bubbles popped at the start of a level; to get the most valuable, seven-level-skip Umbrella, you have to have popped 25 of them. You'll be lucky to see much more than 25 Water Bubbles appear in the first 20 rounds, so you'll probably only be able to trigger one Umbrella in that time. Fortunately, the first two Water Bubble rounds are fairly easy, and with careful play you can pop many of them before the Hurry Up alert appears.

Cane: Makes a giant bonus item appear at end of round

Triggers when you pop 3 of the same EXTEND bubble

Potion: Immediately begins a bonus round

Triggers by wrapping around the screen from bottom to top enough times

Cross: Grants a special attack power

Various triggering conditions

Umbrella: Skips next 3, 5 or 7 rounds

Pop 15, 20 or 25 Water Bubbles

Ring: Grant all candy powers & bonus points for rest of round

Triggers when you eat three of the same candy

The levels

All of that said, here are the first 20 rounds of Bubble Bobble, and how to conquer them, hopefully on the first life:

#1: Difficulty: *

Befitting the first level of such a long game, this one's a breeze. Not only are there only three weak, slow Zen-Chan enemies to deal with, but trapped enemies won't start to escape until nearly the Hurry Up timer. Take advantage of this by blowing a lot of bubbles and popping them, while jumping a lot, to set up Candy items in upcoming rounds.

#2: Difficulty: *

Just one more enemy here than last time. Jump up to the center ledge and bubble the Zen-Chans as they come down. With practice, you can get them all before they fall down further, but if you miss one or two it's not hard to track them down. After they're all bubbled, you can use the rest of the time preparing more Candy, or doing laps back and forth on the bottom level to prime a Shoe powerup.

#3: Difficulty: *

The first thing to do is to immediately jump up to the point to the left of the READY! in the screenshot, and keep firing bubbles to the right until all enemies are encased. Remember, if you clear a level before a special power item appears, you lose it, and if you defeat the last enemy in a level, any special item left uncollected will immediately disappear. Make sure to wait at least 12 seconds to get the item!

#4: Difficulty: *

Jump up to the ledge above you and bubble the Zen-Chans as they fall into range, just like in Round 3. You'll probably start seeing EXTEND bubbles here, which are generated when you pop three or more enemy bubbles at the same time, carried over from previous rounds. Spelling EXTEND will instantly clear the current level, which is good, but also award you an extra life and thus increase the difficulty, which is bad. Still, I usually just go for the letters anyway, because it's fun.

#5: Difficulty: **

This is the first level with Water Bubbles. Try to bubble the four Zen-Chans then hold out on popping the Water Bubbles until Hurry Up begins. Be careful though, the Zen-Chans will probably escape before then and have to be rebubbled. The air currents in this level also tend to draw their bubbles to the top of the screen, where they'll get mixed up with the Water Bubbles. If you end up killing the last enemy by accident don't feel too bad about it, as it frequently happens.

#6: Difficulty: **

This level is similar to the previous one, but two of the Zen-Chans have been replaced by Mightas, which have projectile weapons. Be careful any time you're in a horizontal line with them. It's still early in the game so they'll be slow, but still, bubble them quickly. It's a lot easier to farm Water Bubbles here, and it's possible to get up to 15 popped total by now, but it's best if you stop at 13 or 14, so as to have the best chance of getting a seven-level Umbrella later.

#7: Difficulty: **

Four Mightas appear here. Use the same trick you've been using, standing on the ledge below them and bubbling them as they fall in front of you. By now you should have both long range and rapid fire, which will make it much easier. The Mightas won't stay bubbled as long before escaping, but make sure to grab the special item, which will appear in the upper-right corner, before passing this round.

#8: Difficulty: *

Now that you're decently powered up, you shouldn't have much trouble here. The worst thing about this level is that, once bubbled, the enemies won't cluster together but tend to separate into one group on each side of the screen. You've probably got most, if not all four, of the main powerups by now, and the special items will probably be boring for a few levels.

#9: Difficulty: **

Five Mightas show up. You can handle them the same way as before, but be quick! If you delay even a second, one will probably fire a rock at you. If that happens, drop down a level and try to get them there. Make sure to rebubble them if they start to escape before you pop them, which is pretty likely.

#10: Difficulty: ***

The game is now starting to heat up. Not only is this a particularly chaotic level, but it's also the first one with the bouncing purple Monsta enemies. (The game tends to introduce new enemies on round numbers that are multiples of ten.)

This is one of the levels that caused me to suggest playing on Easy difficulty; if the dynamic difficulty has gotten too high, it's easy for enemies to escape from your bubbles in just a couple of seconds. Play this one carefully. Water Bubbles show up after a short while and can help you clear out the enemies, but be cautious. Keep out of danger and pop whatever you can. It's easy to run out of time if you're too cautious, though. This level is a major stumbling block. Don't use it to farm Water Bubbles or EXTEND letters, just get through it.

#11: Difficulty: ***

At the beginning, quickly jump to the middle island then up to the center ledge. Firing left and right as quickly as you can, bubble all seven enemies as they come down.

Pop the four on the left first. You probably won't have enough time to pop the others before they escape, leaving one angry Monsta and two angry Zen-Chans on the board. The Monsta's not hard to care off: watch its bouncing pattern to predict when it'll come to your horizontal level so you can finish it off. The Zen-Chans will tend to gravitate to the bottom of the screen where they'll jump back and forth across the pits. Fall onto the middle island, on the side they aren't, then bubble and pop them from there.

#12: Difficulty: **

If you're fully powered up, and you're playing on Easy, this one can be finished quickly. Bubble all the Monstas as they rise up, from off the bottom of the screen, into your horizontal line. Then as they drift up, fall through to the top of the screen and crush them. Blowing lots of extra bubbles helps you here; when you pop a bubble, all bubbles that are close to it pop too, and so on, enabling you to pop lots at once if they're in a cluster, even if it extends far across the screen.

If you're not playing on Easy, or the dynamic difficulty has risen enough, some Monstas might escape. Try to pop any stragglers as well as you can. Do not fall into the traps in the sides of the screen unless you need to to pop the last enemy! It's very difficult to escape from them. Water Bubbles spawn on this screen, but it's usually better to go ahead and wipe out the enemies.

#13: Difficulty: **

This would be a very hard round if it weren't for the Water Bubbles that float up from the bottom. Take care of the two Monstas bouncing around outside before focusing on the ones in the heart.

There is a special trick when dealing with all the "elemental" bubbles (Water, Lightning and Fire): their effects tend to spread in the opposite direction to which you are facing. Use this to pop the Water Bubbles at the top of the heart and direct their flows into it, to kill the enemies trapped in there. Don't get swept into the heart yourself unless a really REALLY good prize appears in there, as you'll probably just get killed. Once only enemies inside the heart are left, you can try to farm Water Bubbles, directing the water away from the heart's opening but make sure to kill the last Monstas before the Skel Monsta gets you.

#14: Difficulty: ***

This one's actually not that hard if you follow these steps.

1. Take care of the Mighty that falls beside you.

2. Three Monstas will descend from above. Watch carefully so they don't land on your head, and when they get to your horizontal level dispose of them.

3. The other Mighta will attack from the right now; get it first.

4. Be patient. After a few seconds another Monsta will descend from above. Again, make sure it doesn't hit you on the head, and bubble & pop it when it's in line.

5. Finally, a single mad Monsta will be bouncing around crazily around on the screen. It won't be hard to defeat on its own, but if you've been quick, the special item will still be around, and it could be something fun like a Red Cross, allowing you to fry the last enemy with fireballs.  

#15: Difficulty: **

Try to bubble all three of the enemies in the middle first, and pop them all before moving on to the top. If one escapes back into the middle room, just re-bubble and pop it. If one of their bubbles floats up and out, don't panic, just get it as best as you can.

Be careful with entering the top chamber, jumping from below. Wait for an opening then bubble them all quickly. The special item appears in the top chamber, and is sometimes a Potion. One thing you might consider doing is farming Water Bubbles, which tend to aggregate in the top-right of the screen. If you get stuck in the top before clearing the rest of the board, the flows from the Water Bubbles is your ticket out.

#16: Difficulty: **

Start out quickly, before the enemies activate, by killing the center Monsta as it falls into place, then jump onto the left-hand, single-block platform. As long as you keep shooting left, you're safe here. Bubble the Monstas as they enter range and pop them quick. Repeat for the other side when it's safe, then go up and take care of the last two trapped in the middle of the screen. There is a high chance of a good special item on this board, and it could be an Umbrella. It'd be very nice to skip the next three levels….

#17: Difficulty: **

Do it step by step. First, take care of the Monstas coming up from beneath your starting point. Try to get as many as you can from this perch. When it looks safe, fall and wrap around to the top, which is a good place to bubble remaining Monstas. Watch out for the two Mightas; the only wa

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