The Bugs Bunny Birthday Blowout

This page details one or more prototype versions of The Bugs Bunny Birthday Blowout.

The prototype of The Bugs Bunny Birthday Blowout is a pretty early build. Layouts for the first four worlds have been worked on, though it isn't possible to complete any of the stages at this point.

The ROM image that had been circulating the internet for many years unfortunately had a number of corrupted bytes, which largely affected tilemaps and level layouts. A clean ROM was finally made available in June 2022.

Notes Stage 1The most complete stage, but that's not saying much. Stage 2The obligatory desert stage. Stage 3The volcanic stage. Watch out for lava! Stage 4The barely-started cave areas.

General Differences#

• There are no copyright, title, or story screens. The game throws the player to Stage 1-1 immediately.
• All objects, including Bugs, move at about half the speed they do in the final. This also means that the floating platforms have their ranges halved, making some sections impossible to cross.
• There are no giant carrot objects present, meaning levels cannot be completed.
  • The code for the object is present and partially functional: touching it will cause Bugs to float off the screen in a balloon as in the final version, but the level still does not end, and the music loops indefinitely.
• There is no lives system, so it's not possible to get a game over. Code-wise, the basic framework for the system is in place, but it is hardcoded to jump to the same code path regardless of the life counter's value.
• Enemies and other objects do not display properly, as the game loads an empty bank into the second half of the sprite pattern table.
• Carrot icons do not make a sound when collected.
• Powerup icons do not make a sound or disappear when collected, though they do still set their corresponding flags at $430 in RAM:
  • Speed up (01): This functions as a high jump in the final game.
  • Hammer (02): This would kill more powerful enemies and bosses in one hit, if there were any to actually use it against.
  • Unknown (04): This was replaced with the heart in the final game (see below). There is no code in either the prototype or final game that reads its associated flag, so its intended functionality is unknown.
• Powerup flags are not reset after taking damage or losing a life.
• Crumbling rock platforms are marked with different palettes to identify their type (delayed or immediate).
• Bugs does not dive in and out of tunnels in the prototype. The tunnels behave much more like the pipes in Super Mario Bros.
• There are some debugging functions available: hold Start when starting the game to get a stage select menu, B to start on Stage 2-2, or A to go to a preliminary version of the Mole Game. You can also moon-jump by pressing Select if you are in a stage.
• The Mole Game is more of a graphical demo than an actual game at this point. The moles cannot be hit, Bugs' sprites are glitched (due to a mismatch between his tilemap and the actual CHR layout), and both the music and the game loop indefinitely. It is possible to "end" the game before it starts, though it isn't programmed to simply restart from the beginning when this happens.
  • Lives and carrots are set to placeholder values of 11 and 56, respectively.
• Stages 5 and 6 do not yet exist. Their respective slots load the correct music and graphics, but no tilemaps, level data, or palettes exist in the ROM.

Graphical Differences#

General#

For graphics that appear in multiple levels.

Proto	Final

The disappearing platform in the final was a more complicated spinning platform at this point. The design was simplified to make room for Bugs' diving animation, but while the platform "disappears" it still spins.

So if you were ever wondering why those platforms had weird collision...now you know.

Proto	Final

The graphics of Bugs and the balloon's basket were improved for the final.

Proto	Final

The heart was originally a bunny head next to some odd-looking waves in the prototype. This item sets a flag in RAM in both the prototype and final versions, but no code seems to actually read it; it's possible the item originally served a different purpose, and the heart functionality was tacked on later in development.

This bomb enemy was changed to an alarm clock. Same function, though, and the clock makes more sense thematically.

Proto	Final

Elmer's nets were given more detail in the final.

Title Screen#

Proto	Final

Although the prototype normally bypasses the title screen, it is present in the ROM, and can be seen by changing ROM address 0x1E752 to $40 and holding A as you power on/reset the game. The code to actually start the game is incomplete, and pressing a button here merely causes the screen to fade out and back in.

In the prototype version, the chains are larger, the letters of the title have some shading that was removed in the final, and there are little squares around the border. The Stage 4 music is used here, possibly as a placeholder, though the proper track does exist in the ROM.

Mole Game#

Proto	Final

The mole game has actual moles in the prototype. The graphics were altered into Willy the Weasel.

Proto	Final

This change altered the title graphics as well, replacing the unique graphics of the prototype with a rather plain-looking text box in the final.

Level 4#

Proto	Final

The pipes in this stage are thinner in the prototype.

Level 5#

Proto	Final

The level 5 tileset is seemingly older than the rest, as it does not contain any powerup icons, only a single carrot graphic in a completely different style from the final icons. This was likely changed because, being a background object, it could not be placed on anything but an empty sky background without creating a big ugly hole.

Proto	Final

The inclusion of powerup icons meant that some graphics had to be removed, so the second tile for the tree trunks in the prototype was overwritten in the final. The trunk was also given some additional shading.

Proto	Final

Another victim of tile overwriting: the unique spike graphics were changed to the simpler 8×16 spike tiles used in other levels.

Level 6#

Proto	Final

The lip of the vase was changed slightly in the final.

Proto	Final

The (American) football was redrawn to look more like a...well, football.

Ending#

Again, there's no ending in the prototype, but the graphics are present.

Proto	Final

Bugs' eyes were redrawn to remove the cross-eyed look of the prototype.

Proto	Final

And again.

Proto	Final

Road Runner and Pussyfoot were removed from the photo in the final, probably because they don't actually show up anywhere else in the game. Taz's oddly-proportioned stomach was fixed in the final.

Unused Graphics#

Graphics that are mostly absent from the final.

Mole Game

Various tiles from the Mole Game. Most of these are still present in the final version; only the normal mole head and the first three letters of "SORRY" were removed.

Speedy Gonzales

Yep, it's him. His sprite only appears in the prototype, though there doesn't seem to be an object associated with these graphics.

Spiked Ball

Just a simple spiked ball.

???

These odd tiles take up a character bank in the prototype. It's unknown what they would have been used for, or if they were even intended for this game, though it's possible that the letters were originally intended to be powerup icons before the final icons were implemented as background objects. These were replaced with the Game Over and copyright tiles in the final.

Letters


Letters, presumably coming from an unknown game.

Unknown Level

Fragments of an unknown level.

Audio Differences#

Music#

While the majority of the music is present (if unused), the game over and powerup tracks are not. In the final game, these tracks appear near the very end of the valid track ID list, after the majority of the game's sound effects, possibly indicating that they were a fairly late addition.

There's an extra piece of music in the prototype which is used while Bugs walks into frame. Normally, this cuts off after about one second, but the rest can be heard by changing ROM address 0x1950B to $60. The final game still has a slot reserved for this tune, but it has been replaced with silence.

The death jingle is 20% faster in the final.

The World 3 song has a 2.5-second intro which was removed from the final track.

The bonus stage song is about five seconds longer than the final, and has a different ending. The final version added a second variant of the track that does not loop, which was used in the Willy the Weasel bonus game.

Sound#

Several sound effects have yet to be added, including the pause jingle and the alarm bell that signals the end of the Mole/Willy the Weasel bonus game.

Bugs' hammer sound in the final has a second pulse channel component, which is not the case in the prototype.