This is my second Source venture, and the first that I'm actually proud of. It showcases what I've learned about mapping so far. It's ~10 min of gameplay.
To install just extract the map file in:
...\Steam\steamapps\common\half-life 2\hl2\maps
Then open Half-Life 2, bring up the console and type:
map watertower01
That's it! Enjoy.
Texturing — 4
Ambience — 5
Lighting — 5
Gameplay — 3
The progression to the water tower was great though, it did actually feel like I went through a journey and being able to see the tower from the beginning and being able to see where you began at the end was nice. I would suggest that for your next map that you focus on combat scenarios. Maybe put little spins on them as well for an extra challenge.