This is the full mod version of Station 51, having two chapters. The first is the original map with two changes. Firstly, the part where the Hunters drop from the roof has another section where the door breaks open and two MORE hunters appear. This is a good design choice because originally the battle was ridiculously easy due to having a rocket launcher full of ammo. The second change is that at the part where you pick up the Grav Gun a combine force field is added. It’s a standard Citadel-esque “shoot the energy ball and the path opens”. This was added because you need the GG in chapter two. Since I already talked about this part of the mod in my review of the original map, I’ll skip ahead to chapter two. The airboat you get is pretty pointless since you leave it pretty much instantly. Other than that I love this chapter. The style of it is kind of a cross between the HL2 chapters “Route Canal” and “Water Hazard” (without the airboat of course). It is very well decorated and pleasing to look at. A memorable part for me was going through a slightly maze-esque place filled with zombies and getting to an arena of Combine and Hunters. Then you backtrack and the maze is now filled with Combine. Pretty clever in my opinion.
The last part of the mod is more like the Citadel, except with actual guns instead of just the Supercharged Gravity Gun. It’s very fun to play through but is mostly just wide open areas filled with Combine. Could have been more thought out; the ending is really lazy as well. You go through a portal and it says “Subject Status Unknown”.
Overall, I would say play this mod. It’s great and fun.