Just finished playing Cool gluon, a short Half life 2 map I found on Planet Phillip.
This map was good, that's all though really. A few nice set pieces. Most of the setpieces borrowed from parts of Half life 2 that I haven't seen used in mods too much.
The level design was very nice looking and made for some nice combine battles. Nothing too outstanding though. The puzzles were alright too, but also borrowed a lot from existing puzzles from Half life 2.
The ending was extremely abrupt, but this doesn't bother me too much in short HL2 mods.
In conclusion, this map is worth playing, but there are so many better HL2 mods/maps you could be playing instead.