A single player campaign. You must fight your way to the surface of Black Mesa...
This is a mod that does everything it can to be memorable, the intro of you walking up in your dorm room with personal pictures and then the tram ride... it oozes quality, like everything seems as though it belongs there and there is a lively functioning facility without you having to be there.
The unique locations I haven't seen before, a convenience store and book store. A crystal analysis area... even a new enemy which completely took me by surprise in a really good way.
The combat is great, its evenly spaced out, giving us a rest in between and giving just enough ammo with scarcity for health. Its tougher than HL1 thats for sure. In general you take more damage and theres some large versions of headcrabs I remember from a different mod that spices things up. Also for HL1 mod you take on the black ops at some point.
But what really surprises me is that you meet Barney early on and you can take him with you almost to the end of the mod (and its a long mod so thats really saying something).
My only nitpicks is the lack of puzzles but I've never been a fan of them to be honest and of course the ending, which seemed somewhat abrupt. Like there could have been something more to do, like going out onto a road and breathing a relieving sigh after going through all of that or something.
I noticed lack of music for the credits which is a good way to get people not to sit through it.