It has perhaps the longest (and most dangerous) training mission I've seen :D. Must have been a beta version map that wasn't used and so instead used for "training".
The mod itself is also very long. But while it has some good level design, in its first half... things start to change after you reach the pumping stations. From then on (including the surface levels) its pretty mediocre, random open couryards with some boxes fighting large groups of either headcrabs or grunts.
It gets pretty hard, which might be a good thing for some people but I found it to get pretty frustrating.
Like the introduction of a different low res Islave that can take twice as much damage, and a bigger reddish headcrab that takes alot of damage and moves faster. It seems like the mod was rigged to make it harder... so medium difficulty is actually pretty hard.
There are nitpicks to like some sections pretty much being copy pasted from Blue Shift, HL1, Opposing Force. Though I can only think of about 4 instances so that's not a big deal.
But the repeated voice acting from the previous games gets annoying, some custom voice acting would have helped this mod greatly.
It lacks a storyline or any scripted sequences so it gets stale.
The lack of a ending is the most disappointing thing about it. For such a long mod its a shame to see the creator sort of give up on it.
The mod begins nicely. It's like "OMG! Perfect mod!" - the level design looks nice, triggers and story are fantastic, there are monsters from OPFOR... But after a while I got frustrated:
1. Repeatative level design. Every few maps the style changes in something different, something that copies style of a chapter of HL, OPFOR or BSHIFT and it's very unusual if the style is own made.
2. Copy->paste. There are some areas looking exactly like in BHIFT and OPFOR. With no reason. For nostalgia? I got tired of them placed here and there and combined in different ways.
3. Nonsence level design - most of the maps looks nice, but there are strange things. What is the best entrance for a part of an underground complex with scientists? A vertical ladder which leads to a fenced transformators yard.
4. Nonsence puzzles. Die 10 times to figure out how you pass a "high voltage" place. Plus you get grenades first time at the same place and there are explosive barrels at some places and you think you have to use the grenades to destroy some stuff like in Surface Tenstion in HL1, but no - you just crouch and the electricity doesn't kill you.
5. Repeatative gameplay. Underground->outside->underground, zombies/islaves->marines->zombies/islaves.
6. Crashed because of lack of a model.