Just spent an enjoyable 90 minutes playing Overload 0.6 (early access on Steam).
It's not called Descent because the Descent: Underground folks have the rights to the name, but the actual veterans from Descent are developing Overload. (For example Matt Toschlog, who worked on Descent 3 and helped Duane Johnson port it to Mac.) Emphasis is on single-player whereas D:U is emphasizing multiplayer. This isn't news for some of you, I know..
Anyway I just wanted to post that the game is shaping up great. Runs really smoothly on my Mac Pro 2008 (with GTX 680). Today I played some challenge levels (survival mode, basically) and a couple of the single player levels. Now I feel slightly nauseous and the room is spinning a little. It's just like old times!
Although the game isn't done it's not too early to try it out. I had a problem with fullscreen showing a corrupted screen, but once I'd switched back to windowed mode temporarily the problem never came back (Might have been a corrupted setting from playing the teaser level last year.) It's otherwise been rock solid.