I finished Republic Commando the other day. It was a roughly eight-hour campaign, and I'd say it was pretty good. It's been said that it was too short, however I don't think it was short. I think that the ending was rather abrupt, though, and it makes you feel like crap, considering the context (without spoiling, I'm sure you can surmise why it feels so).
Next up, I'm working on Hexen II. So far it's fairly good. There's a lot of puzzle-y portions, and a lot of back-tracking, and item collecting. It's basically like a first-person action RPG with adventure elements. I should also mention that the engine it's running on was the same that powered Quake, which makes it kind of ugly, but then again I like blocky polygons.
That's it for now. I'll post another update at some point next week, at the latest.