So having spent some time with it, although this mod is fun, it is very buggy and somewhat unfinished.
All the random crashes and errors. Dying any time during the airboat section in the Waterways chapter caused an instant crash on reload, and would crash if I attempted to load most of my save files from that chapter. I am currently in Ravenholm, and having a heck of a time getting through it because the local server keeps disconnecting me and spitting out an error (slightly better than crashing I guess) that I can't remember exactly. Something about the input data and output data not matching up.
As far as functionality, it would be nice if the game used a suit message to at least tell you how to use it. I got quite a ways in before I learned how to change suit modes. Speaking of suit modes, only armor and cloak are actually functional as far as I can tell. Speed Mode doesn't appear to do anything, while Strength Mode turns your punch into a kick without seemingly adding any extra damage, and changes the sound effect of your jump although it does not allow you to jump any higher.
Most of the guns are quite nice, although the silencer on the SCAR appears irredeemably broken, as attempting to select it will cause the gun to stop firing, and even worse, after doing so navigating away from it will result in being unable to select either assault rifle for use until the game is reloaded. The Gravity Gun in this game looks atrocious, as they just recolored the orange part and moved it away from the camera, which has the effect of making your hands look insanely tiny while holding it. Also, for whatever reason, they left the Gravity Gun in but altered it so it only has it's shoot/push mode, lacking the ability to pull in and hold objects, so it's basically a useless weapon. My theory is that they couldn't get around the scene where Alyx gives you the weapon without breaking the game somehow, so they opted for the cheap way out by just gimping the gun to discourage use.
Lastly, I'll just list the little things that bugged me:
1. Your health display will not display any number if it goes under 15, it instead just remains blank until your health has recharged above that point
2. The ammo counter's reserve ammo section is not large enough for the font used, causing the number to go outside the borders and therefor be cut off often. Same goes for suit messages.
3. For some reason, they decided Alyx should be holding her gun in her hand at all times, even when she's in a scene where her hand is open and she's gesturing in a non-hostile environment. It just looks really awkward.
4. Friendly NPC soldiers are almost indistinguishable from enemy soldiers at first glance.
5. Selecting weapons no longer gives you the drop-down menu it used to. This wouldn't be much of a problem if every weapon had it's own key, but they're still separated into categories. I picked up an FY-71 who knows where and didn't know until I accidentally hit the Assault Rifle key twice.
So yeah, fun, but full of problems that need ironing out. At the very least, the guy who made this mod needs to fix all the bugs that actually break the game, like the crashing and disconnecting. They happen often enough to be quite disruptive.