Years after the Borealis Incident, the remaining rebel fighters struggle to find a hero to replace Gordon Freeman. Running low on options, they resort to creating one of their own. An original story set in the Half-Life 2 universe. Re worked weapons, enemies, and even suit functions make for a totally new way to experience the world of Half-Life 2.
This has the perfect amount of detail. It's not cluttered and busy, but it isn't barren. There is enough stuff to make it feel lived-in and real, but also enough room for the player. Very nice.