I have a few, though they are newer and are probably not
utterly unique but are certainly different and not easily, or accidentally, replicated.
The Painter's PlaygroundAt first glance, looks like a shitty MSpaint program. However, you can 'buy' and 'sell' your virtual paintings as if they were real objects. You can trade in the public market, or hang your favs in the gallery for all to see. Some really impressive and beautiful things are still being created, though you might only log in every month or so, it's fun to keep track of different regular artists and see what weird shit has been made.
https://nextzenmechanics.itch.io/the-painters-playgroundAnamesisThis one is a literary, psuedo random story adventure 'click the words and see what happens' kind of game. Interesting world and the systems are a bit obscure, so, unique and different. Lots of weird things can happen, including rivalries and sudden, absolute death.
https://anamnesisgame.blogspot.com/There is a thread on this forum where the dev is pretty active, check it out!
Receiver / Receiver 2Look up some videos on this one, it's super cool. It's an FPS with complex gun mechanics, unique and realistic to every firearm, paired with randomly generated apartment blocks and industrial warehouses. It's you and a gun vs. killer robots of various kinds. What I find most interesting is the goal of each level: find and listen to a variety of
record tapes. Each tape is meant to be a sort of message from your cult, or your organization, that has helped you survive the droid apocalypse. Or at least survive the first wave. The narration is brilliant and the subjects are interesting and thought provoking, and there is a
twist that I will not spoil but it stands out as one of the best experiences I have had in recent years. If you want to see interwoven narrative done right, albeit simply, look no further. The gunplay is intense and has you scrambling.
Middle Earth: Shadow of WarThis one is .. the most generic of this list, however the nemesis mechanic is so. damn. amazing that it's still worth talking about all these years later. You can direct yourself to youtube if you still haven't heard about this game, but the just of it is that enemy troops are given their own stories and experience and levels. As you explore the world, you encounter these soldiers with random traits, in sometimes deadly combinations! My favorite element is that, should a lowly orc manage to finish you (the Hero of Tamriel, or whatever) off, they can be promoted and join the gang of head-honcho orcs.
What no one told me is that the game comes with a secondary, permadeath-enabled mode, complete with a completely alternate set of warriors and special artifacts, including a hang glider and a grappling hook. This is honestly the most fun I've had in a while - just trying to set a new high score on the toughest difficulty, knowing I have no second chances. You really come to rely on your bodyguards, which gain levels and skill alongside you as you bring them into battle. If they die, they die and you have to recruit a new one, which is expensive.
I will say, this game trashes LOTR and it's lore. Like much of the new media surrounding these stories, take what you can get, and skip the rest. Hollywood nonsense, including giant death worms and 'numenarian' technology makes for cheese.