@SaulFabre Please forgive me, I completely forgot about this.
Right now I finished testing
RetroArch 1.17.0 and here's my findings according to the cores that I use.
If you were expecting me to test ALL of the cores, well... I do not do that as I'm not interested in, say, Commodore, or ZX Spectrum, or Virtual Boy, etc.
Atari Core flat-out doesn't work.
CPS1 has crackling sound.
CPS2 has crackling sound.
FBAlpha has minor crackling sound. It's there, but it's less apparent than with other cores.
ALL GAMEBOY CORES has crackling sound.
MAME2000 has crackling sound.
ALL NES CORES has crackling sound.
NXEngine (CaveStory) has crackling sound.
ALL SEGA CORES has crackling sound with the novelty that Genesis Plus GX Wide doesn't work now.
ALL SNES CORES are broken. They won't recognize my .sfc or .smc files.
ALL PCE CORES has crackling sound.
ALL WONDERSWAN CORES has crackling sound.
Wow! What a nice update!
About raiden2.zip, use Core G to load it. Now you'll see it's stuck at Diagnostic Mode screen.
Press Select to open Quick Menu. Go to Options. Go to Display MAME menu -> enabled
Press Select to go back to game. Select Dip Switches. Select Test Mode ON and change to OFF.
Now Raiden2 will start with garbled graphics and no sound and you can't controll it. But it starts.