Long Night.
This game is a fork of Naev (
https://naev.org/) and is similar in graphics and style, but it has a different storyline and a larger universe and has still a different gameplay feel to it. It's hard to describe … If you know Naev, it's very similar, but also does many things differently, like a completely reworked trading system or that every planet has its own backstory, etc. I had tons of fun playing it and I gave a lengthy review about bugs and such.

Like Naev, Long Night is incomplete. It was posted in the old Naev forums, but the forums have been lost (sadly).
It's very hard nowadays to obtain a copy of Long Night today, I don't think I have one anymore … So yeah, I definitely think Long Night qualifies as obscure.

EDIT: Oh, I remember it now! The game was eventually renamed to Nox Imperii:
http://noximperii.comIt's still an obscure game, however.
