Colecovision Ghost&Zombies is a very much shortened version. There´s no scrolling and it has just few screens. Several years ago Dvik made a fantastic smooth scrolling Ghost´n´Goblins first stage demo for MSX. I think the sprites were far bigger than on C64 conversion. It was discussed at least in Karoshi forum. I am afraiding that those demos are not downloadable anymore, maybe you should contact Dvik and ask for that demo. In the same discussion somebody converted Nes G´n´G music to MSX. Yes, it sounded good, but as you know, it was not The Music you are wanting to hear, it doesn´t sound anything like C64 tune was, naturally. Decades ago it was not a nice moment to hear that Amiga conversion doesn´t have same music as C64 G´n´G, but arcade game tune (which Nes conversion has too), which really isn´t anywhere as moody as C64 tune.