Do you mean "Sword of The Stars The Pit" by Kerberos?
If so: yeah I played through the demo, and enjoyed it -- but haven't played it again. I think it's "hard" in the sense that there is a lot to learn about the secondary systems (like all the various crafting tools and recipes). There is a lot of apparent depth to the game; for but some reason, I wasn't really compelled to replay it.
Certainly worth a look at the free demo, of course, and they clearly put a lot of work into it -- despite the clumsy name, I hope it's doing well :-)