Way more gimmicky than 2, but still a fun platformer. Sadly David Wise didn't do the music for this one, soundtrack isn't as great as the first two games.
Very fun campaign. The library sucks though and it tends to repeat some level themes. Aside from that it's a classic. Also bonus points because you can kill Sergeant Johnson and it's funny lol
Probably the worst part of HL2. Really nothing new that wasn't in 2, not much new in terms of story, and not many memorable setpieces outside of the ending. Also the dark areas suck. Not really worth going back to after playing through it once.