A few hours after Adrian Shephard and his squat got scattered allover the Black Mesa Complex, headquarter sent a rescue team to search the lost crew.
This review may contain spoilers
I think one of the major gripes I had with this mod is that it relies too much on puzzles as a gameplay element, which isn't a problem in and of itself - but Half-Life was designed as an action game with some simple puzzles thrown in, and for "adventure-style" puzzles like those in this mod to work properly, they need to be done well. Unfortunately many of the puzzles are quite obtuse - for instance I didn't realize that the security guard at one point was preventing me from picking up the key card, and I just happened to press the fire alarm afterwards to "lure" him down - I didn't realize this was what you were supposed to do until after reading it on this page.
Another issue is that due to the puzzle nature of the mod, there is alot of backtracking - and the problem here is that there are many long, slow elevator rides between sections. This is annoying in and of itself, but even more so when you need to use them multiple times. I must admit I noclipped a couple of times. Maybe some simple staircases would have worked better.
On a positive note, and something this mod really did great - many of the setpieces are fantastic - my favorite being the train ride near the end, albeit silly and unrealistic, it was quite entertaining, and made up for the tedious puzzle-heavy section leading up to it.
The mapping, detail-wise, is quite good, although I think there is a bit too much use of tiny brush-details - some custom textures/models might have worked wonders.
Unfortunately I often had a feeling of being on a "carnival", going from one ride (i.e setpiece) to the next - I didn't feel any real sense of place or purpose, and certainly not of Black Mesa (the bricked sections, for instance, felt quite out of place). Also I think some more action inbetween (with more weapons available) could have been a good idea.
Little space left, so bugs: got a powerful pc but still got fps drops in the test chamber; got stuck on geometry/objects numerous times; cyclers spurt blood