From time to time, I've criticized the OSR for losing sight of its raison d'être—keeping old D&D alive—when it goes off the rails and veers into creating games that aren't even the least little bit compatible with D&D. Can you really call a game "OSR" if it's functionally indistinguishable from any other "indie" RPG? I don't think so. But I only get significant pushback for this opinion on the r/osr sub-reddit, where I'm apt to be slapped with a familiar and oft-repeated refrain: "What good are endless parades of retro-clones? It's not like we need yet another B/X rehash!"
And that's true. We don't need any more retro-clones. The cloning business is mostly over and done with. Every classical edition of D&D has its faithful clones: white box has Swords & Wizardry and Delving Deeper and White Box Fantastic Medieval Adventure Game and Iron Falcon; blue box has Blueholme; pink box has BFRPG and Labyrinth Lord and OSE; red box has… well, okay, there is no faithful red box clone, so that's a bit of a glaring omission, but then the Rules Cyclopedia has Dark Dungeons, which is honestly close enough. 1st Edition has OSRIC and 2nd Edition has For Gold and Glory.
So I think it's safe to say that the clone thing is covered. Which raises the question: if the old rules are all published, and new rules that don't work with the old game are of no particular interest to dedicated players of old D&D, why publish any rules at all?
The clones, of course, came into being to provide legal cover for producing content—adventures, settings, supplements, and so forth. It was a way of resuscitating support for formerly dead games. And bow-howdy was that ever successful: if you're a TSR D&D player these days? There is now a huge library of new content to draw upon. But there's a limit to how useful these things are, particularly if you prefer to create your own settings and adventures and dungeons. I don't really use other people's settings at all, for example, and I certainly prefer to avoid adventure modules entirely, if I'm able.
The second reason to publish a clone game is to get your fantasy heartbreaker out into the world. This is the proverbial "D&D plus my house-rules" type game. Which, okay, I'm not going to fault anyone for putting in the effort to do that, but interest is bound to be limited. We all have our own preferred house-rules, after all, and sometimes it's easier to just share the house-rules! No need to build a whole game around them!
But the third reason to make a retro game is one that warms my heart, and not just because I have a personal stake in it: the genre-bash! Taking the D&D rules out of the fantasy Middle Ages and setting the game in some other period or genre! Now that's where it's at! The OSR has been a resounding success in this area, to a degree that can only be compared with the "d20 boom" of the early 2000s, when it seemed like every game and every genre was being converted to the D&D 3rd Edition d20 System.
Having a d20 conversion of every game was convenient and useful, but it also exposed some of the glaring problems with the d20 System. It just… wasn't good for lots of genres. Oh, sure, I had a lot of these games back in the day—Swashbuckling Adventures (the 7th Sea conversion), Oriental Adventures (which, unlike the AD&D 1E book, was a d20 L5R conversion in all but name), the d20 Stargate and Farscape and Star Wars RPGs, OGL Steampunk, and of course the elephant in the room, d20 Modern (with attendant supplements d20 Future, d20 Past, and Urban Arcana, as well as the Pulp Heroes mini-game from Dungeon Magazine/Polyhedron). But… to say that these games were a little broken is a wild understatement. To point out that some of them were complex to the point of unwieldy (here's lookin' at you, Stargate d20) is laugh-out-loud comedy.
When the same phenomenon is applied to the OSR, though—to the various white box or pink box conversions of some of these same genres—the results aren't a hot mess. They're a glorious mess.
You want sci-fi? Stars Without Number is crazy popular even beyond the OSR niche, but I prefer White Star by a country mile. So my space opera gaming is covered. Post-apocalypse? I've also got Mutant Future waiting on my shelf.
Present-day action and espionage? You've got White Lies, which is brilliant. Want some urban fantasy? Just add supernatural elements from any other OSR game to this one; or lean into it, with Esoteric Enterprises.
Early 20th century pulp? Between B/X Gangbusters, Amazing Adventures, and Raiders of the Lost Artifacts, I never need to touch the d6 System Indiana Jones game or Savage Worlds ever again.
Once we're into the 19th century, we of course have my own Engines & Empires, which is geared to Victorian steampunk but can handle the Old West just fine as well (although there are of course many OSR games specialized to that genre, such as Tall Tales B/X). A Ghastly Affair is the same deal for 18th century Gothic horror, and Freebooters covers the golden age of piracy. For early modern or pike-and-shot era historical gaming, there's Miseries & Misfortunes, and of course Lamentations of the Flame Princess is basically "Solomon Kane B/X." (Really, have you ever sat down at taken a close look at LotFP? It does not change the B/X rules very much at all.)
For anything renaissance or medieval, straight-up D&D will do you just fine. Ancient periods are covered by Mazes & Minotaurs, and if you want antediluvian sword & sorcery, you've got Jason Vey's Hyborean Age rules for OD&D (or Through Sunken Lands, which sadly doesn't have a print version yet). To say nothing of the aptly-named Astonishing Swordsmen & Sorcerers of Hyperborea…
The only other genres I might care to run sometime (since I don't particularly like horror or super-heroes, although both do exist in spades for the OSR as well) are epic high fantasy, and sword & planet. The first is held well in hand with Beyond the Wall and The Hero's Journey; and the second has more Barsoom-inspired rulesets (with names as varied as Warriors of Mars and Warriors of the Red Planet) than you can shake a stick at.
So… I guess what I'm saying is, for all the useless artpunk drivel that the OSR has produced in the last ten years or so, there's nevertheless a ton of worthwhile content still being made. Some of these titles are straight-up gems, brining the OD&D rules into practically every genre worth playing an RPG in. And unlike the d20 System, these conversions mostly work. Best of all, you can usually mix and match disparate games without difficulty or conversion, to a degree that the various d20 System games really couldn't ever handle well (because of the complex interactions between various sub-systems, even innocuous character-building elements like skills and feats).
I'll soon be getting a 1920s pulp adventure game off the ground that bashes Raiders and Amazing Adventures together, with the centerpiece being one of the earliest dungeons ever published for D&D—Palace of the Vampire Queen! (Though I'm usually hard on modules, I can't find a flaw with PotVQ! Its room-descriptions are delightfully terse, basically one line each, and every single dungeon floor's key fits on two pages! It's pretty much the same format I'm working into my Fiendish Temple module—and it's been around for 45 years, with basically nobody making use of it in all this time! A topic for another day, I suppose…) And the notion that I can play a pulp game with what are still essentially the OD&D rules kicking around under the hood… that's what has me really excited for this game. I can play an Indiana Jones meets the Mummy style campaign, and I don't have to learn some non-D&D system in order to do it!
This joy—this revelry in the familiar—is practically heretical in some RPG-playing circles. If you think r/osr is wild, let me tell you, the r/rpg sub-reddit is a real trip. Those folks have a constant anti-D&D hate-boner over there that makes rpg.net look practically welcoming and inviting even on its worst day. At least twice a week, there's a new thread popping up on r/rpg where someone is either whining that they can't convince their players to play a system that isn't D&D, or they're lamenting the fact that nobody plays their favorite pet system on Roll20, or they're just complaining about how overwhelmingly popular D&D 5e is. (Which, okay, fair—D&D 5e deserves any amount of hate people are willing to direct at it. But it should be hated because it's a bad expression of D&D, not because it's a popular game!) I often wonder whether these complaining GMs who can't get their favorite system off the ground are just unable to assert themselves, or whether they're woefully tied to groups of players who don't want the same things out of RPGs that they do (perhaps because they only play with friends); but I digress.
I find myself feeling a certain perverse glee at the fact that all my gaming needs are fulfilled by OD&D and a short list of OSR genre-bashers that allow me to run OD&D games set in practically any other genre or period. It feels like spitting in the face of some RPG snob who thinks that if you're into D&D, you must also be "into" other RPGs, as if interest in a variety of game systems were some sort of hobby requirement. I'm reminded of the Richard Dawkins quote, "Although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist." In a similar sort of way (though I'll freely admit, the analogy is a stretch, and I do hope you'll pardon the mangled turn of phrase), the OSR has made it possible to be a "genre fulfilled D&D player"! ∎