Under the Microscope: Fighting Vipers Taikenban

In this edition:

• The trial disc for Fighting Vipers secretly has a full build of the game behind its demo restrictions.
• That build is from 1996-07-24, right in between the earliest available prototype and the final NTSC-J version.
• This version has some interesting differences, like a “Virtua Fighter Pai” costume for Honey and an unfinished design for Pepsiman

I made a patch to lift the demo restrictions, allowing this build to be explored — get it from SegaXtreme. Here’s a video!

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Intro

Fighting Vipers Taikenban is the trial version of Fighting Vipers. It lets you do three fights in Arcade mode before sending you to the Game Over screen.

The disc has more files on it than it needs, however: all of the .STG ones are present. Can they be made playable?

Yes! The demo restrictions are fairly superficial, and with them out of the way we can explore a more-or-less full build of Fighting Vipers. It’s from 25 days before the final version, and while it’s more complete than the 1996-07-05 build, there are still several unfinished elements.

Below are some notes about the unique features in this build and technical details on the demo restrictions.

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The final weeks of development

The bonus characters — Mahler, B.M., Kumachan, Pepsiman, the various alternate Honeys — aren’t implemented in the 1996-07-05 prototype. But some of them are here in this build, so they must have been added in between the 5th and 24th.

Here’s Pepsiman in the Arcade mode character select screen. His portrait differs from the one in the final version:

The character select screen in the other modes has evolved to look more like the final version’s:

Neither of the prerelease builds has the second row fully implemented. You can select the bonus characters if they’re unlocked, but they don’t have portraits.

Interestingly, the second row seems to have 8 slots rather than the 7 in the final version. Who’s the extra character? It’s Pai Costume Honey, of course! In a previous article I described a patch to the final game that makes her available. She’s present in this build.

School Uniform Honey and Hawaiian Outfit Honey are also present, but the game seems to crash when you put certain combinations of Honeys together. I wonder if this was why the Pai costume was cut?

The Options menu is functional, but lacks the visual polish of the final version:

The Options Plus menu is rougher — not everything is there, and whatever Flag Set is, it doesn’t actually work:

The hidden Backup Debugger arguably looks better in this version, though:

Some other notes:

• Team Battle Mode is in the menu, but it crashes when you launch it.
• Training Mode works, but it crashes if you try to leave it.
• Versus Mode also works, but player 2’s character choice isn’t respected.
• Playback Mode has several exhibition matches available, but their labels don’t match their contents and player 2 often has no health. Also, the HUD is different (see the screenshot and video above)

The credits mode is supposed to show recorded bits of your fights with the other Vipers, but in this version there is no staff roll and the scenes are actually playable!

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Lifting demo restrictions

The mode select screen in the demo only lets you choose Arcade Mode or Versus Mode. It does this by resetting the cursor after index 01, but we can restore the full list with these patches:

06034fe6 ed08  # Wrap around after 8 items instead of 1
06034f68 ed08  # Wrap around to item 8

The menu items are mislabeled after this, however – everything is off by one. We can fix that with these patches:

060351a8 0009  # Skip the menu item offset
060351c0 00d4  # Make it so Arcade mode still works

The bonus characters can be unlocked by reading in static values for their flags:

060391ac e1ff
06029cf4 07ff
0602a0a6 ffff

We can keep fighting after the third opponent with this patch:

0601d232 e009 # 9 fights instead of 3

And we can see the unfinished credits with this patch:

0601d178 e00d # Credits instead of game over

One editorial choice I made was this: the game has you fighting Bahn, Grace, and Pepsiman. The remaining fights are then all with Pepsiman. I changed the list to match the final game, except I put Pai Costume Honey into Honey’s place.

06027ab0 01  # Bahn
06027ab1 02  # Grace
06027ab2 07  # Picky
06027ab3 03  # Tokio
06027ab4 04  # Sanman
06027ab5 0b  # Pai Costume Honey
06027ab6 02  # Raxel
06027ab7 05  # Jane
06027ab8 0f  # B.M.

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Outro

For more Saturn hacks and cheats, see my archive here at SHIRO!. And for more articles on retro game reverse engineering, see my Rings of Saturn blog.