Bubble Symphony (Arcade)

This page contains notes for the game Bubble Symphony (Arcade).

Difficulty#

Difficulty is based on three variables.

• Rank (40ED3C) is the master variable of the dynamic difficulty system. Ranges from 0 to 30.
• CooldownVar (40ED3E) will either add to or subtract from Rank depending on how long it's been since a new game was started. Ranges from 0 to 31.
• RankFloor (40ED40) is the lowest possible value that Rank can be set to. Note that this is only checked when subtracting from Rank; the game can add to Rank and still have it be under this value. Ranges from 0 to 30.

What Affects Difficulty#

When the machine boots...

• CooldownVar is set to 10.

In attract mode...

• The game adds 1 to CooldownVar every time the high score screen is viewed.
• For game demos, Rank is set to 7, RankFloor is set to 0, and all of the adjustments listed below are skipped.

At the start of the game...

• Rank is set to one of four values based on the game's difficulty setting: Easy is 4, Normal is 7, Hard is 10, and Very Hard is 13.
• RankFloor is also set according to difficulty: Easy is 0, Normal is 2, Hard is 4, and Very Hard is 6.
• A value based on CooldownVar is either added to or subtracted from Rank:

At the start of each stage, if Rank is 15 or less:

• The game checks the number of rounds that the player has completed without dying. If the value is even, the game adds 1 to Rank.

In a two-player game, the game does this check for both players.

• The game then compares this deathless round variable with a value in the first column of the table below. If it's equal to or greater than that value, the following occurs:

:*If RankFloor is less than the value in the second column, RankFloor will be set to that value.

:*If Rank is less than the value in the third column, RankFloor will be set to that value.

In the case of a two-player game, the game will use the lower of both players' deathless round values for this check.

At the start of each stage, if Rank is 16 or higher:

• The game checks how long the player has been playing on their current credit. If the value exceeds the value in the first column, then RankFloor will be set to the value in the second column unless it's already greater than or equal to that value:

In the case of a two-player game, the game will use the longer of both players' timers for this check.

After getting a Game Over and reaching the high score screen...

• CooldownVar is set to either 0 if a player got a high score or 1 if they didn't.

The following events immediately affect Rank:

• Starting a two-player game adds 3.
• A second player joining a one-player game adds 3.
• Losing a life subtracts 1.
• Either player continuing from a game over in a two-player game adds 3.
• Spelling out "EXTEND" adds 1.
• Collecting any key adds 1.
• Entering any secret room adds 3.

What Difficulty Affects#

• Special Item Requirements: See next section.
• "Hurry Up!" Timer Adjustment: If the value of Rank is 16 or higher, the amount of time that the player has before the "Hurry Up!" sequence starts is shortened by up to 7 seconds:

• Skel-Monsta Timer Adjustment : If the value of Rank is 16 or higher, the amount of time that the player has before Skel-Monsta appears is shortened by up to 7 seconds:

• Monster Speed Adjustment: If the value of Rank is 16 or higher, the speed of Monsters is increased.

(The meaning of this value depends on each monster's movement code.)

Special Item Conditions#

Each special item has four different thresholds that the game checks to determine whether or not it should spawn. For example, for a Cross of Thunder to appear, the player has to collect either 10 (D1), 12 (D2), 14 (D3), or 16 (D4) point items. The threshold that the game checks depends on the value of Rank at the start of the stage:

:*D1: 0 to 3.

:*D2: 4 to 7.

:*D3: 8 to 11

:*D4: 12 to 30.

The table below is checked from top to bottom, and the game will select the first item it finds that has its requirements met. When an item is selected to spawn, its counter is cleared. Counters otherwise keep their values from game-to-game and are only reset when the cabinet is reset.

ID	Item	Value	D1	D2	D3	D4	Condition	Effect
0E6		1,000	—				Enter "BUNNY" on the high score screen.	At the end of the stage: All bubbles turn into 700 point Bunny Girls. A Big Bunny Girl worth 100,000 points drops down from the top of the screen.
149		10	777				Start X stages.	Gives the player an extra life!
14A		5,000	40				Collect X big point items.	Reveals the location of hidden Notes in the next 2 stages.
11D		20	40				Spawn Skel-Monsta X times.	Summons a purple comet that initiates the "HURRY UP!" sequence.
11E		10	20				Die by Skel-Monsta X times.	Instantly spawns Skel-Monsta.
0E7		2,000	10				Trigger "HURRY UP!" X times.	Chimes and screen flashes red if any offensive special item is set to spawn this stage.
129		3,000	—				Enter "GIRL" on the high score screen.	Summons a Bunny Girl as an assist character.
0DB		500	4				Collect X red "E" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Soda Popsicles. A Big Soda Popsicle worth 10,000 points drops down from the top of the screen.
0DC		500	4				Collect X "X" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Chocolate Popsicles A Big Chocolate Popsicle worth 10,000 points drops down from the top of the screen.
0DD		500	4				Collect X "T" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Oranges. A Big Orange worth 20,000 points drops down from the top of the screen.
0DE		500	4				Collect X blue "E" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Watermelons. A Big Watermelon worth 20,000 points drops down from the top of the screen.
0DF		500	4				Collect X "N" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Eclairs. A Big Eclair worth 30,000 points drops down from the top of the screen.
0E0		500	4				Collect X "D" Extend Bubbles.	At the end of the stage: All bubbles turn into 700 point Shortcakes. A Big Shortcake worth 30,000 points drops down from the top of the screen.
0E3		1,000	3				Collect X Books of Death.	At the end of the stage: All bubbles turn into 700 point Yellow Diamonds. A Big Yellow Diamond worth 70,000 points drops down from the top of the screen.
0E2		1,000	3				Collect X Crosses of Thunder.	At the end of the stage: All bubbles turn into 700 point Blue-Purple Diamonds. A Big Blue-Purple Diamond worth 40,000 points drops down from the top of the screen.
0E1		1,000	3				Collect X Crosses of Water.	At the end of the stage: All bubbles turn into 700 point Blue Diamonds. A Big Blue Diamond worth 50,000 points drops down from the top of the screen.
0DA		5,000	15	20	25	30	Start X stages.	Spawns a yellow spark that ricochets around the stage, destroying any enemies it hits. Enemies drop 6,000 point Purple Diamonds.
117		4,000	20				Start X new games.	After clearing the stage, 10 Extend Bubbles are added to the game's reserve.
126		3,000	50	51	52	53	Pop X Water Bubbles.	Summons a large purple bubble dragon as an assist character.
124		3,000	45	46	47	48	Pop X Water Bubbles.	Summons Chack'n as an assist character.
123		3,000	40	41	42	43	Pop X Water Bubbles.	Summons Tiki as an assist character.
122		3,000	35	36	37	38	Pop X Water Bubbles.	Summons Hippopo as an assist character.
121		3,000	30	31	32	33	Pop X Water Bubbles.	Summons Bob as an assist character.
120		3,000	25	26	27	28	Pop X Water Bubbles.	Summons Ptolemy as an assist character.
11F		3,000	20	21	22	23	Pop X Water Bubbles.	Summons the Cannon from Space Invaders as an assist character.
0F1		3,000	16	18	20	22	Defeat X enemies with Thunder Bubbles.	Conjures a star storm that destroys all enemies. Enemies drop 6,000 point Purple Diamonds.
0F2		3,000	16	18	20	22	Defeat X enemies with Rainbow Bubbles.	Intense sunlight destroys all enemies. Enemies drop 10,000 point Chocolate Cakes.
0F0		3,000	16	18	20	22	Defeat X enemies with Fire Bubbles.	Triggers an earthquake, destroying all enemies. Enemies drop 8,000 point Yellow Diamonds.
10B		1,000	16	18	20	22	Defeat X enemies with Wind Bubbles.	Destroys enemies with holy light. Enemies drop 10,000 point Gold Crowns.
10A		1,000	60				Collect X end-of-stage drops.	Doubles the value of popped enemies for the duration of the stage.
0EE		3,000	10	12	14	16	Collect X special items.	Floods the stage, drowning all enemies. Enemies drop 7,000 point Blue Diamonds.
131		3,000	10	12	14	16	Defeat X enemies with Water Bubbles†.	Gives the player 16 uses of fire breath for the current stage.
0EF		3,000	10	12	14	16	Collect X point items.	Conjures a thunderstorm. Enemies hit by lightning bolts drop 8,000 point Yellow Diamonds.
10C		1,000	80				Collect X treasure items.	Changes all enemies into Zen-chan.
0D9		1,000	6				Collect X Pink Candies.	Player gains 100 points when blowing bubbles for the duration of the stage.
0D8		1,000	6				Collect X Green Candies.	Player gains 500 points per jump and 50 points per bounce for the duration of the stage.
0D7		1,000	6				Collect X Blue Candies.	Player gains 10 points per frame while walking for the duration of the stage.
127		3,000	1				Collect X Big Onusa.	Summons Sayo-chan as an assist character.
128		3,000	1				Collect X Big Magic Staves.	Summons Mr. Mikata (1P) or Peppl (2P) as an assist character.
125		3,000	1				Collect X Big Red Items.	Summons Silver Hawk as an assist character.
0D6		3,000	40	40	50	60	Collect X monster drops.	For 20 seconds, enemies freeze and are destroyed on contact. Drops vary based on species.
0D5		300	29				Fall into X pits.	Turns the stage into a card-collecting bonus game with Joker Cards.
0D4		300	28				Fall into X pits.	Turns the stage into a card-collecting bonus game with Diamond Cards.
0D3		300	27				Fall into X pits.	Turns the stage into a card-collecting bonus game with Club Cards.
0D2		300	26				Fall into X pits.	Turns the stage into a card-collecting bonus game with Heart Cards.
0D1		300	25				Fall into X pits.	Turns the stage into a card-collecting bonus game with Spade Cards.
0D0		200	70	80	90	100	Pop X Fire Bubbles.	Explodes, destroying all enemies. Enemies drop 10,000 point Blue-Purple Diamonds.
0CF		200	100				Pop X Thunder Bubbles.	Stops time for 20 seconds.
109		1,000	100				Pop X Rainbow Bubbles.	Slows down enemy movement for 20 seconds.
12F		2,000	100				Pop X Wind Bubbles.	Greatly slows down the stage's air currents for 20 seconds.
102		1,200	20				Collect X bubble potions.	Transforms all bubbles on the field into 700 point White Turnips.
101		1,200	18				Collect X bubble potions.	Transforms all bubbles on the field into 700 point Red Turnips
100		1,200	16				Collect X bubble potions.	Transforms all bubbles on the field into 700 point Onions.
0FF		1,200	14				Collect X bubble potions.	Transforms all bubbles on the field into 700 point Carrots.
0FE		1,200	12				Collect X bubble potions.	Transforms all bubbles on the field into 700 point Eggplants.
0FD		1,200	10				Collect X bubble potions.	Transforms all bubbles on the field into 700 point Green Peppers.
0CE		1,000	24,576				Walk for X frames.	Increases player's speed by 3.
0CB		100	3,072				Walk for X frames.	Increases player's speed by 1. Can be stacked up to three times.
0CA		100	35				Perform X jumps.	Enables rapid fire bubble blowing.
0C9		100	35				Pop X normal bubbles.	Increases player's bubble speed by 3. Can't be stacked.
0C8		100	35				Shoot X normal bubbles.	Increases player's bubble range by 3. Can't be stacked.

Glossary

• Point items: These items spawn in a stage's point item slot two seconds after the stage starts.
• Special items: These items spawn in a stage's special item slot seven seconds after the stage starts.
• Big point items: Includes the items that drop down at the end of a stage after collecting a Top Hat, Treasure Chest, or Magic Cane, and the Big Diamonds that appear after collecting three Notes when the player already has a key of the same color.
  
  The Big Diamonds that pop out of treasure chests do not count as big point items.
• Monster drops: Any item that spawns from the body of a defeated monster. The lone exceptions to this are the Gold Crowns created by the Holy Grail item, which are counted as point items.
• Treasure items: Includes all items that pop out of treasure chests and the Diamonds that appear in secret rooms.

Counter Anomalies#

• Items that share the same conditions share the same counter, except for the Taito Coin and the Magic Necklace. Both check the number of stages started, but they use different counters: The Magic Necklace counter is at 40EA6A in RAM, and the Taito Coin counter is at 40EA6C.
• The requirements for item 0CE make it nigh-impossible to get without credit feeding. For reference, 24,576 frames is equal to about 6 minutes and 50 seconds of walking. They'd also have to avoid having the Shoes spawn, which would reset the counter.
• The counter for the Cross of Fire is bugged. Instead of increasing by 1 every time an enemy is defeated by a Water Bubble, it instead increases by 1 every frame a burst Water Bubble comes into contact with a bubbled enemy.
• Hippopo's water bombs count as Water Bubbles for the purposes of the Cross of Fire and Pink Heart / Scroll counters.
• The Big Candy item adds 1 to each candy collection counter.
• The game keeps track of how many keys have been collected at 40EA8A in RAM, but no special item uses this as a spawn condition.

Miscellaneous#

When the game is generating ceiling / pit bubbles, there's a small chance that a Special Bubble will spawn. The Special Bubble gives sixteen uses of fire breath for five stages. In Bubble Symphony, the chance of one spawning is even rarer than in the original Bubble Bobble: 1 in 16,384. The code for this starts at 0x44B02 in the main CPU.