as mentioned, it's in a weird limbo state where the active devs are more interested in having it run on obscure portable devices rather than putting together a solid windows build that would be useful to the average guy.
that said, looks like one guy is (finally) aiming to do that;
https://github.com/MeeperTheGreat99/systemshock-enhanced/releasesI'm hoping his next release will have FMsel integrated, maybe even support for higher resolutions (I'm pushing things around a bit behind the scenes, as I tend to). the plan is to have it integrated into SSPtool once the few necessary features are in (cfgs finally in the game root now, modern resolution support would be very nice but no idea whether this is going to be in the next build, and
SS2 UI interactions would be amazing but zero idea about that).