I have many love and hate issues with 1187, while I mostly enjoyed the progression between locations, characters and how they present a Half Life 2 prequel, it tends to fall flat on the lack of direction, some odd design decisions and other issues presented in the review.
Browsing tag: HL2 Theme: Underground
Mission Improbable
While it not exactly a mod that provides a lot of challenge, the levels are paced well and are gorgeous to look at, with several detailed environments, nice use of colour correction to spice up the atmosphere and the addition of many smaller ideas to keep things fresh.
Powerstation 17
The setup is simple but the map is enjoyable from the get go, with moody underground segments and solid mapping all round.