Let's start by saying it's a great remake of HL1. I played it back in 2012 when Crowbar Collective released the free version. What can I say?

Advantages:
1) Great graphics. Overall beauty of the world geometry is amazing.
2) Details. Every level, model, texture and particle is made 'with love' and looks like it's suppose to be there. There's no feeling like 'oh, why this door is here' or whatever like that.
3) Brilliant voice lines. I don't know if you asked the original actors to record voice lines, but it feels extremely native to HL atmosphere and very professional.
4) Hi-Tech and Sci-Fi. All these highly advanced machines, generators, teleporters are amazing. Nothing to say more. For me it's heaven to play Lambda Core all over again.
5) Hit registration. Not sure if you did something special to lagcompensation/raytracing system in multiplayer, but it's just perfect as it supposed to be.

Disadvantages:
1) Prediction. What is that??? Why predict when we can not! The prediction system in this game is completely broken. You don't see anything wrong in SP, but as soon as you join a MP game to some high-latency server you'll see and hear that all sounds and effects are doubled. It feels like your programmers forgot to put SuppressHostEvents before running prediction. It does crash all the time the game is trying to predict for falldamage sound on Lambda Bunker map.
2) Paticles/muzzle flash effects in MP. You definetely did something wrong to these two aspects. Even on my PC it's lagging as hell when someone is shooting on your screen, but it doesn't when you shoot yourself! Feels like something to do with DLight allocation.
3) MP balance. When I first joined the MP game, I felt like I played it already for my whole life. You did some really good job balancing weapons/damage/health/armor. However, it feels like you appreciate 'luck' in this game, since every explosive weapon is completely overpowered in MP. RPG. You can just pick it up and it doesn't matter if you're good or not - you can just shoot the enemy with 100/100 with one shot in close range BUT you wont die! Even if you had less then 100 HP and no AP, you'll be still alive, but your enemy with 100/100 not. It is OK? Satchels. You can just throw them in to enemy and just press M2. Your enemy is dead. Doesn't require any skills to do so and moreover most of people are doing it in a very 'rat' way. Crossbow. Zoom with it is just fine (except for sensetivity), but explosive mode is just overpowered as well. You can pick it up, face 100/100 enemy and shoot 4-5 arrows to his feet and he's dead. Tripmines. What's wrong with their hitbox? You almost have to face it to explode with bullets. The dot product shoud be > 0.7 to hit it. Not really convinient. Grenades. Why do you use QPhysics for grenades? It's 2016 outside. Moreover you don't see the grenade itself when someone is throwing it at you. Trails and sprites (like in HL2DM/TF2) would be really nice to see in updates.

I would love to help you guys with these issues, so feel free to add me any time.

XEN more like WHEN

Black Mesa offers gamers to experience the action and survival packed world of Half-Life again by utilizing the capabilites and elegance of Source engine.

The game has stunning visuals. Adding the physics capabilites of Source engine to the gorgeous graphics takes your gaming experience to another level.

I think it is a game that every Half-Life fan should play and have in his/her library. I highly recommend it.

Team Crowbar has written a love letter to Half-Life and Valve, and it was well worth the wait. This was extremely fun to play through. If you love Half-Life, and you want to run around a secret underground science facility shooting aliens and marines, look no further.

HALF LIFE
BEST LIFE

Amazing game! Loved every bit of storyline...it was a really great remake of HL1!

A remake of the best Valve game ever to exist.

10/10 What more do you need?

Black Mesa is a faithful remake of Half Life for a modern audience, but still retains the elements which made the original so revered - challenging platforming and combat, a lack of hand holding and complete immersion into the extraordinary world.

Cool game, brings back all the nostalgic moments together with HD graphics. Thats all. But that RARE SPECIMENT ACHIVEMENT is one hell of a journey

I played this back before it was put on steam, and I was Impressed as well as satisfied with the then finished product. I went and picked up the steam version to show my support for the dev team and letit sit in my library for a while, and recently replayed through it when my internet was out - It's improved.

I reran the original Half life countless times over, and Opposing force, and Blueshift, and now I seriously wish that both of those were remastered in such a stupendous manner as Black Mesa. The characters are much more alive, the dialog is crisp, the visuals are modernized and appreciable in their merits, but most importantly it's actually a refreshing take on the old game.

Certain portions have changed since GoldSource, some puzzles have been removed and replaced with different ones (Mostly it appears for the sake of the older puzzles not fitting with the updated visuals) and the overall experience is revamped. I actually felt sorry for one of the Guards at one point into the storyline, which baffled me seeing as how many times I've given Half Life a run through.

TL;DR To summarize without any more rambling, Black Mesa is worth paying for, and I cannot wait for the release of Xen to complete the game.