Underhell is a Source Engine game developed by the Underhell Team in collaboration with We Create Stuff. Underhell Chapter 1 requires ONLY Source SDK Base 2007 installed. No Source game is required.
The story makes everything around you disappear, makes you only live in it until it ends, and that's what I believe only the best of the best stories can accomplish. And there's great music.
Variety of locations, quests and plot twists are amazing, and the mod will take about 20 hours, but it almost never feels protracted despite the length.
Characters are well written, and it's entertaining to hear what they have to say. And skins of their heads look great. Amazing what a simple high-resolution picture can do.
It's a great idea to put in two storylines of the character - his personal life (develops in the house), and his professional career (develops in the chapters), and I really look forward to see how these two will eventually intersect.
But why only 5/10?
For every thing that made me love this mod, there was something that made me hate it.
Battles were annoying (maybe that's just me though) due to health depleting too quickly. And when I got the hang of it, the authors started to spawn crowds of enemies!
Bugs play a serious role in spoiling the impression:
One time I rescued a survivor, and when I escorted him to safe zone, everybody acted as if he didn't exist, and he continued to follow me. Immersion breaker.
Each loading is a risk, as the game may crash or freeze so hard that even the Task Manager won't be able to close hl2.exe process. I actually couldn't finish the mod (good thing that the ending can be seen on YouTube) due to stable crash at the Chapter 2's first checkpoint - the game crashed before it could save (apparently any disk-write crashes it at this point, because when I tried to make a screenshot it also crashed). And trying again involved sitting through a 10-minute scene, "skip cutscene" key I found in the keyboard settings didn't work...
To conclude - play it, but not now. Wait for update with better content, stable code, improved gameplay balance. You will benefit from the wait as you won't have to deal with the unripe product.