Station 51 (HL2: Ep. 2)
Now a mod, with a whole new second level! Check it out here on ModDB: Station 51
Built using the lessons learned from A Brief Detour, Station 51 is a single player level set in the Half-Life 2 universe. You're a rebel escaping from the Combine forces closing in on your rooftop outpost.
The level is action focused, with sprawling, deathmatch style combat arenas that give the player and NPCs room to flank and maneuver around each other. There's a mix of cover with plenty of open space, along with lots of vertical differentials and many alternate paths.
The open spaces give the player freedom to explore without feeling lost. The player is subtly nudged along with breadcrumbs like strategically placed items, visual highlights, and enemy spawns.
I got some great feedback from some early releases – encounters that were too difficult or too easy, paths that weren't clearly communicated – and was able to incorporate that feedback back into the map.
"Sam knows what he is doing and playing this release shows that" – PlanetPhillip.com