House of the Dead 2 multiplayer bug

[Widge]

hi all. I wasn't sure exactly where this post should go, but Support seemed like the most appropriate section. If I'm wrong, then please move it if possible, or let me know to delete and repost.


House of the Dead 2 on Dreamcast has a pretty significant bug that I haven't seen talked about much anywhere.

If two players are playing together with lightguns, whenever they both shoot at exactly the same time, Player 1's shot is repressed and only Player 2's shot fires. Otherwise, player 1 fires normally the rest of the time, it only manifests when the triggers are pulled exactly together.

A North American friend of mine first told me about this bug a year or two ago (I'm European). I have since tested multiple revisions of the game across several regions and they all have this bug. I have tested with a real Dreamcast console and with the Flycast emulator. Although, I wasn't able to test the USA release on a real Dreamcast because that version locks out authentic Sega lightguns and I only have Sega guns, I could test it on Flycast and it is affected.

I think this is the only game with the bug, Confidential Mission certainly doesn't have it. Also, the Naomi arcade version of HotD2 doesn't have the bug.

I haven't been able to find much more information about this bug. Nobody else seems to have documented it, I guess not many people play this multiplayer with lightguns because it can be pretty crippling to P1 when you both are shooting rapidly together.

I wonder if someone here with knowledge of hacking roms and patching might be able to find the root of the bug and produce a patch for it. Unfortunately I have no knowledge or experience and wouldn't even know how to begin.

So, has anybody else here noticed this bug? Has anybody ever looked into its cause? Is anybody here willing to tackle it?

Edit -- I applied the region unlock patch to the USA HotD2 rom just to complete the testing and confirmed that it is also affected. I also patched and tried Death Crimson OX and that is also affected. Death Crimson 2 also seems to be affected.
So to summarise, games affected by this bug are HotD2, DC-OX, DC2.
Games not affected are Confidential Mission, Virtua Cop 2

[Xiden]

Never noticed this back in the day, no wonder 2 player mode seemed harder lol