I’ve been helping Kale with a few simple tasks on Hyper Neogeo 64, for example, adding support for the alt tilemap dimensions needed at one point in the Roads Edge intro for the rotating title screen.
The original hardware material found on YouTube is a blessing for such things, as the hardware has quite a few effects and features which are only ever used in one place (due to the limited number of games on the hardware)
3D still isn’t working for most games, and the sprites are still a complete mess in many cases (there is no clear sprite disable / enable register per-sprite at all) but improvements are being made. Due to the limited test cases, and (in places) rather wacky hardware this is quite a tricky system to emulate, so could still be some years away from working properly. Thankfully it seems a lot of the odd hardware (the Z80 clone with MMU etc.) probably doesn’t matter too much. We’ve asked somebody (I won’t name them unless they want to be named) to look at the sound too which is running off a v30 based chip, but again has extra features like an MMU, which may, or may not be required for emulation.
*edit*Kale improved sprite clearing in Samurai Shodown 64 1/2, and I found a place which makes use of global sprite scroll registers (the ranking screen) Again this seems to be a feature only used in one place. They scroll most of the sprites by changing the global scroll value, while allowing another sprite to remain static by adjusting it’s scroll positions to counter the global scrolling.
