I'm going to revisit editions of D&D here, talk a bit about their most faithful retroclones, and what to play instead of bothering with either. I've skipped some editions not worth discussion.
1974 Original D&D AKA OD&D, Brown Box D&D, White Box D&D
Gary couldn't write a book to save his life. There was a lot of inferred knowledge required for the game, specifically Outdoor Survival (a terrible board game), and Chainmail (a meh miniature battle game). Furthermore Grayhawk is the worst supplement ever in the supplement treadmill of D&D, because it would be a harbinger of things to come, unnecessary bloat in the form of the Thief class, unnecessary convolution in the form of multiple die types representing weapons and hit dice. The most faithful version of the original box is a free game called Full Metal Plate Mail. What you should play instead is Swords & Wizardry White Box. If you crack open the game and it has a thief class, you have the wrong game. S&W White Box is the best, most hackable simple D&D on the market that is broadly compatible with OD&D with next to no conversion.
1977 Holmes Basic AKA Blue Book D&D (AKA Original D&D for morons)
So there are people who love Holmes D&D. It's bad. It was apparently written from the standpoint of a guy who appeared to play D&D wrong, never met or discussed his interpretations of the game with Gygax, and shat those interpretations into his own retelling of early-level whitebox. I would assume the closest retroclone is Blueholme Prentice, but in truth I don't really care. Swords & Wizardry White Box is the far superior game for this flavor of D&D.
1978 Advanced Dungeons & Dragons AKA First Edition
Remember when I said Gygax couldn't write a book to save his life? Well that's still the case here. Parsing the PHB of AD&D is tough, and honestly not worth it. The DMG is a useful resource that could have been made more useful with a better author and editor, because books aren't made to have ~14 appendices, regardless of the novelty now. The closest retroclone is OSRIC. What you should play instead is Swords & Wizardry Complete, which hews closer to OD&D with all the options turned on (which is like 90% of AD&D), but has the Swords & Wizardry flair baked in that simply isn't present in the AD&D rules.
1981 Basic/Expert D&D AKA B/X D&D, Moldvay Basic
This one gets a whole lot of love, but having such a small game in two books is just a super pain in the ass. The game itself isn't too bad, mind you, but there is better. The closest retroclone is Old-School Essentials. The bad news is that's a re-edit you have to pay for, which makes it the first version of the game on this list you have to pay for. What you should play instead is Basic Fantasy RPG. It's so much cheaper you can buy the entire Basic Fantasy line for the same price as the OSE corebook alone. That's like 15 books at the current time. And all the PDFs are free online. It's stupid that OSE has more of a following than Basic Fantasy.
1989 Advanced Dungeons & Dragons 2E AKA Second Edition
Really the reason I made this post. 2E holds a dear place in my heart. Wow is this edition a pile of trash on fire blowing in a hurricane of feces. No bones about it, I love this edition, my game-brain still thinks in this edition's terms. I'll never not have d8 be my default damage die that I think in terms of (longsword), I'll never not reach for a d10 when someone says "roll for initiative". That being said, it's a convoluted mess that deserves no praise beyond the settings it introduced. I outlined a way long ago to play the game while eliminating the most egregious problems with the system. The closest retroclone is For Gold & Glory. What you should play instead is how I got into the OSR in the first place.
1991 D&D Rules Cyclopedia AKA BECMI Revised, One Book D&D
The only reason BECMI isn't on the list is that I'd have to write the same entry twice. The cyclopedia is a fully contained version of D&D in one book. It's ok. I don't hate it. It's like a step between B/X and AD&D, which makes it worse than B/X (see recent rant about OSE being hard to hack). That being said it's one of the better hacks of B/X to exist. It's most faithful retroclone is Dark Dungeons. What you should play instead is Dark Dungeons X, because it includes the high-level play of BECMI but also has rules baked in to improve the experience, including reskinning the out-of-genre monk/mystic/whatever class to a werewolf which is brilliant.
2000: Dungeons & Dragons 3.0 AKA Third Edition, Three Point Oh, Turd Edition, WotC Fantasy Game formerly known as D&D
The paradox is that the OSR was born out of this edition (and it's slapdash patch job in the form of it's later version) sucking all the ass. It's closest clone is Pathfinder 1E. What you should be playing is any OSR game at all that's not based on 3E or later. Because it sucking fucks and fucking sucks. Even the shittiest, most barebones, most restating regurgitating retroclone has more heart and understanding of core design principles of D&D above and beyond this edition or any that came after it. I'd rather play Labyrinth Lord.
