Steam

Looking into it, ZOOM Platform is run by the Jordan Freeman Group, which has a similar mission statement to GOG, that being a DRM-free games platform that also touches up and sells old games. They seem to have acquired publishing rights to the FlatOut trilogy, along with either source code or enough resources to touch them up without it. I didn't know about them until this post, so it's nice to see that GOG isn't the only DRM-free old-games platform around.