Extending the demos: Frame Gride (Dreamcast)

Getting more out of your demo discs by changing a few bytes

Frame Gride is a mech fighting game developed by From Software, who would later be famous for the Dark Souls and Elden Ring games. It’s the only From Software game to be published for a Sega console.

The final game was built on 1999-07-05 and released a few weeks later. A couple of demo discs preceded it: Frame Gride Pilot Style (built on 1999-02-26) and Frame Gride Test Operation Disc (1999-05-10). This article is about those demo discs – I’ve made patches that let you go beyond their limits and play extra stages. One of these stages doesn’t appear in the final game!

You can get the patches from SegaXtreme! Here’s a video of the unused stage in action:

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Pilot Style Taikenban (version 1.002)

Cover scan via Sega Retro

This demo is from almost four months before the final game. Normally it lets you play as one of the mechs (with three different color choices) in one of the stages. However, the game has data for two additional stages.

When you’re highlighting a stage on the map, the value at 8c33e8d4 changes from -1 to the index of the target stage. The playable level, Silent Forest, is index 02:

The function at 8c03a58a is handling this value assignment. To determine whether to show a stage as playable, it checks the table starting at 8c33e8e8 to see whether it’s nonzero for the target stage.

That table gets written by the function at 8c03a7a0. My patch makes it always write a nonzero value:

8c03a868 01e2  # Always read a 1 from the table

Now you can highlight all of the available stages. Most of them don’t actually work, but Forgotten Temple does. Note that it has different lighting and a different background from the final version:

Left: The prototype demo. Right: The final game.

The Deep Cave stage also works. This one looks closer to the final version:

Left: The prototype demo. Right: The final game.

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Test Operation Disc (version 1.005)

Cover scan via Sega Retro

I was able to do even more with this later disc, which is from almost two months before the final version.

The function at 8c05def8 runs when the mech preparation screen is active. It grays out some of the menu items by checking the table at 8cd13d94 for nonzero values. This patch makes that check always pass:

8c05dff0 01e0  # Always read a 1 from the table

Now you can choose a different style of mech:

The demo lets you pick from a few different colors, but this patch makes them all available:

8c05e310  0fe4  # Color menu maximum is 0x0f
8c05e322  00e3  # Color menu minimum is 0x00

The color selection screen differs noticeably from the final version:

Left: The prototype demo. Right: The final game.

The demo normally lets you play the Fallen Bridge and Forgotten Temple stages, but it’s also got data for Silent Forest, Deep Cave, Opera House, and Fossil Desert.

Opera House doesn’t appear in the final game at all! It’s replaced with Grudge Arena:

Left: The prototype demo. Right: The final game.

Opera House and Grudge Arena look totally different:

Left: The prototype demo. Right: The final game.

Fossil Desert differs a little bit from the final version — notice the sky color and rougher textures:

Left: The prototype demo. Right: The final game.

I made these extra stages available with this patch:

8c05b742 0900  # Set every stage's availability value to 0x01

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Outro

For more on prototype builds rescued from discs, see my archive. Which other demo discs might be hiding extra prerelease content? Give me your suggestions in the comments.

Logo by Ashlyn Anstee

Thanks for reading Rings of Saturn! I have a few more articles on retro game reverse engineering to deliver in 2025, and have many more in store for 2026.