Originally Posted by Teknoman
Wait so the Golden Axe on the Sega CD collection has a different soundtrack?
Yes, the 4-in-1 and 5-in-1 collection discs' version of Godlen Axe has some nice CD audio music, but is one player only, sadly. Otherwise it is the same as the Genesis game.
The other games on the discs are much less changed -- none of the others have CD audio soundtracks added, only Golden Axe -- but I think there are some minor sound-effect changes or something, I forget the details.
Originally Posted by lazygecko
It was probably more work than expected, since it wasn't possible to just put the roms on a CD and load them up from there. They had to actually manually port the games over. This also led to some interesting subtle differences in the games that did get ported, like Golden Axe using the original arcade music as CD audio, and Streets of Rage using different higher fidelity voice samples.
Yeah, it's difficult because the SCD only connects to the Genesis through that fairly small bus on the side. While the bus that connects the Turbo CD to Turbografx is wider, apparently only a limited amount of data can fit on the SCD bus, or something, if I remember right (Of course the SCD has a LOT more RAM than the TCD sans Arcade Card, so the SCD has the advantage there. But it has limitations as well.). Combine this with other restrictions, and SCD games can actually have more limited animation than Genesis games because of hardware restrictions, or something like that. I think this is one reason why Pier Solar didn't have a Sega CD version, but instead is a Genesis game with that CD soundtrack disc. The hardware restrictions are surely also why Golden Axe had its two player mode removed, though it's a bit weird considering that Streets of Rage is on the same disc and is two player... sure, that doesn't have an added CD audio soundtrack, but still.