Post subject: Daffy Duck The Marvin Missions
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Looks like I'm not getting around making a topic for this game. Apparently the health bug from the SGB version is actually still present in the GB version. Nobody just ever bothered to check it properly... When you do it and the health runs out, the game will glitch up severely, slowing down and not showing sprites anymore. It will need some investigation...
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So I just tested it for an hour. Bizhawk(Gambatte): Crazy stuff can happen, random jumps to the title screen, game over screen, super stage screen... Random jumps to a new room with all enemies being different and glitched... Crashes... VBA 19~23 VBA 24 BGB 1.5.1: No variety in the glitch. It is really always the same flickering and the game is slowed down a lot but nothing else happens. Occasional crashes. Gameboy Advance Gameboy Player: Black screen. Black screen and literally nothing else but a black screen with no sound. I don't know if the ROM I used is different from the cart I used. I don't know what is the correct emulation. BGB and Gambatte both have 89.4% in the GB Accuracy test but have a different emulation of the glitch (with the same ROM used). And the real consoles had a different outcome with no visual glitching whatsoever.
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Link to video Played on Bizhawk 1.11.1 Gambatte core BK2 download Note: This still syncs in 1.11.7.
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Apparently you can do a glitch at 3rd boss to insta-kill him. https://www.youtube.com/watch?v=FV4vfiWswA8#t=4m40s
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I noticed something. The current console record for any% by Chancool clips onto the plate right away whereas the current TAS doesn't. Chancool told me he always clips onto it, it just happens. Seems like an emulation difference/inaccuracy then...? I know I was able to clip onto plates in other rooms years ago when the any% route wasn't discovered yet. It kind of depended on whether you crouched in the previous room or something. Needs looking into. Edit: Wait a second. Getting on the plate is actually a bad thing. The TAS skips it and goes to the next room faster. So nevermind.
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Chancool improved his run by not crouching before the plate room (so he didn't teleport on the plate). Their new time is 1m57s.
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I'm discussing the health bug with Chancool.
  • When Chancool does it on his DMG-YS-NOE1 cart on SGB2 SGB1, the game freezes.
  • When I do it on my DMG-YS-NOE-1 cart on GBA/GBPlayer, the game freezes on a black screen always.
Either there are differences between the systems or we both had a different cart (different revision?). It would be great if we had more people testing the bug on their consoles. I researched the bug a bit on emulator. It happens on GB because the game cannot handle you having 0x3F health. At the same time, I noticed the game considers Daffy to be dead if the value is 0xBB. Either the bug is related to rendering/sprites (The game tries to display the health bar but messes up). Or it is related to the game's coding (it tries to run wrong code based on the health address).
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Tested the gameboy version's 0 health bug in different SGB cores in Bizhawk. Bizhawk 2.1.0 PizzaBoy --> Same as VBA/BGB (flashing indefinitely, nothing interesting) Bizhawk 2.1.1 SameBoy --> Always white screen with very faint garbage audio
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Tried the health bug (GB version) on the new Gambatte core in Bizhawk and the results are vastly different from the previous core. Instead of "crazy stuff can happen", it's now just a white freeze screen, with a slight chance of there being few glitchy sprites along with it, but that's it. Nothing seems to ever be happening which also seems more in line with what was happening on the real console (black screen only).
GJTASer2018
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So would it be safe to assume the "crazy stuff can happen" was the result of inaccurate emulation (like the pipe glitch in Super Mario Land 2)?
c-square wrote:
Yes, standard runs are needed and very appreciated here too
Dylon Stejakoski wrote:
Me and the boys starting over our games of choice for the infinityieth time in a row because of just-found optimizations
^ Why I don't have any submissions despite being on the forums for years now...
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GJTASer2018 wrote:
So would it be safe to assume the "crazy stuff can happen" was the result of inaccurate emulation (like the pipe glitch in Super Mario Land 2)?
Yes, inaccurate emulation probably. The only thing that was inaccurate emulation about the pipe glitch was the old days of VBA though, that put breakable blocks where there shouldn't be any. Everything else about pipe glitch is accurate, as evidenced by console players. Can't say anything about pause bug, since it is too precise to do on console, but then again nobody tried it (might take like a thousand attempts to get anything?). That would actually be the next step to SML2 console RTA.
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Do you know anyone with that Gamecube Gameboy player setup mentioned in those Pokemon TASes? Seems like it's possible to console verify what might be errors and what may be real.
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No, I don't know anyone. Getting a card from ebay should be fairly easy though. But I don't think anything will arise from more looking into it. The now "more accurate" (?) Gambatte is much closer to the test results on the real console, with a frozen screen, so I think that's all there is to it.