Even though this game simply oozes with love, it still looks and plays like a good amateur-ish mod, not a full release worth of its money. The gameplay is somewhat worse than the original, general production values are approximately on a level of a mid-to-low-budget game from 2007, and overall jankiness is so persistent it can't be ignored. Total neglect for stuff from Blue Shift and Opposing Force is also noteworthy, not to mention the screwed-up visual design, like Xen being turned into your average alien jungle, or modern-day marines in what's supposed to be an alternative 1990s setting.
Black Mesa isn't worth its price and most of the good things it has are remnants from the original game.
In conclusion, it's a nice try, but still a lot worse than the OG Half-Life, which aged like a fine wine and didn't need a remake in the first place.