Extending the demo: Wild Arms (PlayStation)

Hacking into a prerelease build of Wild Arms (1996)

In a previous edition, I wrote about a cheat code for Wild Arms, the 1996 RPG from Media Vision and Sony. That cheat code activated the game’s debug mode, which, among other things, allows you to warp to arbitrary locations.

The Map screen in the NTSC-U version of Wild Arms

While doing my recent survey of the PlayStation demo discs, I noticed that Sony published a preview version of Wild Arms in Japan about a month before the retail game.

I’ve written before about using debug features to explore beyond the usual limits in demo discs. So I wondered: is it possible to enable debug mode in this prerelease version of Wild Arms?

Answer: yes. I’ve developed a patch that makes the necessary changes. Download it from GitHub. Details are below…

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Enabling debug mode

In the retail version of Wild Arms, the function that listens for the debug mode code begins with logic like this:

def check_debug_code_80143b28(pressed_button):
    if (debug_code_entered_8001101f == 0) and (pressed_button != 0):
        ...  # Check for the 24 button sequence

That is, it checks to see whether the debug code has already been entered. If it has, it doesn’t bother looking for it again.

The preview version of Wild Arms has a version of this function at 8013a0a0 with the same logic. The only difference is that it has debug_code_entered_8001101f set to 1 by default (rather than 0). This effectively blocks debug mode from being enabled.

Changing that default removes this limitation. Interestingly, the preview version uses a button sequence that’s different from the one the retail version uses:

L2, L2, R2, R2, L1, L1, R1, R1, Left, Circle, Right, Square, Select

But since we’re changing defaults already, we might as well just enable debug mode directly - why require a code? My patch changes the first instruction that touches the debug mode flag (which is stored at 8001101d) from a read to a write:

8013a4ac li v1,0x1      # Load an immediate 1
8013a4b0 sb v1,0x0(v0)  # Store it in the debug flag's address

With debug mode enabled, we can see interesting things about this demo build.

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Build differences

One thing that’s immediately noticeable: when debug mode is enabled, you can use the D-pad to move the “Trial version” badge around the title screen. L1 and R1 rotate it; L2 and R2 make it zoom.

Moving the badge around

This feature isn’t in the retail version, as it doesn’t have a corresponding badge.

During gameplay, you can get to the Map screen, which allows you to warp to different areas by:

• Pressing L1+R1+Select to enable coordinate display.

• Pressing Triangle to open the Action menu.

• Navigating to the 6th item on the Action menu (Options) and pressing Circle.

• Navigating to the 10th item on the Options menu and pressing Circle.

The demo version of the game has a different set of locations than the retail version - some areas are missing, and others are greyed out.

Left: The prerelease demo. Right: The retail game.

Many of the areas that can be accessed in both versions match up. However, some of these are unfinished. For example, D19 doesn’t have flashing red floor tiles in the demo version:

Left: The prerelease demo. Right: The retail game.

And the demo’s version of E26 doesn’t have the cutscene that’s in the retail version:

Some areas don’t match at all. For example E15 takes you to one scene in the demo and to an entirely different one in the retail version.

Left: The prerelease demo. Right: The retail game.

There are dozens of maps to examine, so if you’re a fan of this game, give the patch a try. Leave a comment if you find something cool!

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Outro

There’s also a prerelease demo of Wild Arms: 2nd Ignition that predates the final version. Although it shares a lot of code with Wild Arms, it doesn’t seem to have the Map change feature. If I figure out a way to make it explorable, I’ll post about it.

Thanks for reading! I’ll be back with another edition soon.