Luckily the final segment, with Riddick back in the dark where he belongs, helps the campaign win back your heart. In my book, three quarters or more of good game and one quarter mediocre game still makes a decent game overall, and even when Assault on Dark Athena is at its worst I never found it less than engaging. Were it a proper sequel I'd probably expect something more, but as an expansion it's easily good enough to complement Butcher Bay.
The final portion is, of course, the multiplayer. Sadly, and in the interests of full disclosure, I can't really tell you much about it. Why? Well, I only have pre-production, pre-release code and the servers have only just gone live. I'm reliably informed that the Pitch Black mode, with one player playing Riddick while the others hunt him, is a hoot while the other modes are a bit take ‘em or leave ‘em. If you feel different, leave your comments in the usual place, and I'll add mine when I get a proper retail box.
For me, multiplayer isn't really the point, anyway. Riddick was always about delivering a visceral, narrative-driven single-player FPS. Starbreeze showed it could do this with Escape from Butcher Bay, then showed it could do it again with The Darkness. Now, Assault on Dark Athena - while the weakest of the bunch - makes it a hat-trick. It's still way beyond anything you might call average, and in its best moments it's very good indeed. That's enough to keep me going, enough to re-inspire the Riddick faithful, and enough to keep Starbreeze in the frame as one of the most interesting action game developers around.
Assault on Dark Athena isn't consistently as great as Butcher Bay, but it's still a fine hybrid stealth/FPS. Put the two games together, and you have an exceptional package.