Hello, I'm pretty sure this is a very difficult thing to get fixed, but, here it goes.
I'm able to use MAME to emulate a Philips CD-I, as it was something MESS was supposed to do, and it got merged with MAME (so, I'm sorry if i'm posting this on the wrong area)
There's an issue with the infamous Zelda CD-I games, Faces of Evil and Wand of Gamelon, since those games rely heavily on cutscenes that are overlayed on top of the current scenario.
The emulator is able to play those cutscenes.... But as long as you use a very unusual Workaround.
You see, most of these cutscenes are triggered by you making some action, like talking to a NPC, or entering an area via a door.
If you simply talk to the NPC or enter the area, the game hangs until your press another button. Pressing it will "skip the cutscene" and resume regular gameplay.
However, if you trigger the cutscene while holding any of the two buttons the CD-I has.... the game hangs as well, but this time, the cutscene will start as soon as you let go of the button.
Even if you start holding the button after the game freezes (indicating it's loading the cutscene) and before the sprites disappear (which is when the CD-I should start playing it) it'll play correctly. As long as you're holding any of the two buttons when the sprites disappear, the cutscene plays once you let it go.
As this didn't happen in the standalone CDIEmu (which MESS emulation seems to be based off, way back then. MESS got a lot better than it), I'm assuming this is not its correct behaviour.
I know this is a very minor glitch, for a system that's not a major interest of most people, and it's emulation development efforts were probably halted way back in 2009, but... It's still a glitch, and I'd like to see it fixed XD
Oh, by the way, since the beginning cutscene doesn't need special transparent effects until its last 5 seconds, it plays properly even without that workaround. So if you're testing it, I'd say to go to Goronu on FoE or Sakado in WoG, enter the nearest building (the shop in both games) and talk to the merchant (by slashing him with your sword. Logic.)