Lutris can provide a similar function but it is substantially more complex than what minigalaxy offers. Minigalaxy is in it's infancy but at this point seems to be functional and I think it would make a great addition to the already superb lineup of gaming tools and clients on Solus.
It is open source under the GNU General Public License Version 3
I think it will get a good/large audience if it is well known by the Solus gaming community, as the official GOG client has yet to come to linux. I think (if it works well that is) it would get a good amount of users as a GOG client seems to be on the wishlist of a lot of Linux users in general. Granted we are a smaller community when compared to say Ubuntu, But I believe the Solus gaming community would be a quick adopter of minigalaxy, that is for those that are in the cross-over of "I use Solus and GOG.com".