Method

The Patch-a-Bobble graphic user interface.

The selected levels are inserted into the original game ROMs by using a custom version of an old level editor called Patch-a-Bobble, by Karl Stenerud. The “custom” bit comes from the fact that the editor has two problematic flaws – it doesn’t let you insert the “Drunk” enemy and, what’s more, it has a nasty bug in positioning enemies on screen, so that what you see on the editor is not what you get in game. Bisboch, the founder of the project, was then lucky enough to randomly stumble into Aladar on a forum. Aladar, as a skilled coder, was (and is) on an epic quest to port Bubble Bobble on the PC Engine. Moreover, he was kind enough to create a custom fix for the Patch-a-Bobble issues, on Bisboch’s request. That’s how Aladar came onboard on the Lost Cave Project.

Originally, the process was meant to be totally handmade; the original level was played, documented and then, block by block, stat by stat, ported to the coin-op via Patch-a-Bobble. This method shows a lot of romantic devotion, but there are good chances of introducing mistakes, since the natural limits of human performance, especially when it comes to airflows – those invisible streams which make bubbles graciously float around.

Level 92 from the NES version, with airflows displayed, thanks to the Bubbled editor.

An important help came from Bubbled, a NES Bubble Bobble level editor by Tedd Robb, which allows to read the NES BB ROM and to make airflows visible. What’s more, Bubbled makes all sort of stats and timings visible, so that it’s relatively easy to transfer it via the Patch-a-Bobble GUI.

But how to deal with the Game Boy and Game Boy Color versions? Spotting airflows thru’ a trial-and-error process with that little game window and the scrolling was a true pain in the ass. That’s where Aladar once again saved the day, with an in-depth analysis of both the GB and GBC down to enemy coordinates and everything else.

Aladar worked more and more on creating ad-hoc tools to make Bisboch editing work easy, starting with an automation system which will make the transfer from GB/GBC to coin-op even faster, with almost no need for manual intervention.

When every bit of the selected hundred levels from the home/handheld versions finally found place in the coin-op ROM data, the team start working to make sure they’d fit nicely all together, following a coherent difficulty curve modeled after the one of the coin-op.

Having still some free time before the planned release date, we decided to broaden our scope by updating the graphics too. At first, Bisboch selected the best bonus items which originally appeared only on the home/handheld versions, and injected them into the coin-op gfx ROMs by using an old arcade graphics editor called TURACO (again, fixed by Aladar in order to properly work with Bubble Bobble). Aladar then created some tools to inject new graphics freely into many screens of the game, by allowing me to alter the original tilemaps. This means not only a new title logo and a new ending screen, but also brand new secret screens with new secret messages too!

This brought to a even more ambitious plan: to change the way the secrets of the game work, including the secret codes you need to use to see the real ending of the game. Basically, you need to find out again how to reach the good ending, since your old Super Bubble Bobble (and Power Up and Original Game…) codes won’t work in the Lost Cave!

This way, you’re forced to discover this “new” game the same way you discovered Bubble Bobble many yoears ago: by playing, initially without cheats or help. Of course, with MAME it’s easy to cheat, buy we’d really love to see  the player discover slowly with the many new surprises we put into this level hack of ours.

Will you find the final treasure? We’re not in 1986, many things have changed for videogames and for players, and the final message you’ll find at the bottom of The Lost Cave may be different from what you’d expect…