Run. Think. Shoot. Live. Source. Black Mesa is the Half-Life 2 total conversion of the original Half-Life game. Utilizing the Source engine and its endless array of possibilities and powers, Black Mesa will throw you into the world that started the Half-Life continuum and introduced Gordon Freeman to the world as a gun-toting, bullet-dodging Ph.D. in Theoretical Physics.
This review may contain spoilers
It its true sense the Black Mesa Mod for HL2 stays true to its purpose: to update Half-Life 1 to a more modern gameplay.
Most levels featured from complete faithfulness to the original with minor tweaks levels to a complete overhaul of design, dynamics and length.
I welcomed some changes, like the better availability of ammunition for weapons like the Magnum, which acted like a sniper hand cannon, addition of new puzzles (Valve puzzles? I see what you did there) and level progression.
The enemies behave as expected, with marines working using cover and squad tactics and flushing out you from cover with grenades, Xen creatures behaving like animals and generally avoiding (aside headcrabs and zombies) avoiding barnacles which they should be familiar with.
As I mentioned some levels were overhauled to the point where even if you played HL1 enough times to know them by heart (I know I did) you'd feel like you're playing in a new and different level, well because you are. Some parts between Surface Tension and Forget about Freeman have almost been completely axed out, not to mention the Transit system you use to reach the rocket launch area being reduced to half of what it used to be. The addition of bosses like the chopper at the dam and again at the canyons are very well welcome break from the original.
The voice acting is on par with many professional games with in game jokes, situational comments not only for characters you interact but also your enemies, although I miss the Vortigaunts shouting "DIE" before they zap you, the addition of crucial key characters like Dr. Elli and Dr. Kline (is that how it's spelled?) help maintaining the game's relation with its sequel.
Some of the weapons lost its usefulness like the pistol no longer being the sniper pistol and the sub-machine gun being useless most of the times save when you need the grenade launcher.
Overall it is a great and memorable mod, I'm looking forward to the Xen levels.