Greentext

It's not a trilogy, but I gotta preach the good word of Ender Lilies: Quietus of the Knights. If you enjoy 2D metroidvania style games it's top notch.

The game just drips in atmosphere. The environments are beautifully drawn and designed, characters and enemies are animated well and the music just wraps everything up in a nice bow. It's a melancholy game and it literally made me cry at points and I'm not the type to tear up often when playing games.

The game can be challenging at times, but I wouldn't say significantly so. I would say Hollow Knight is more challenging than this game especially with some of the end game content that that game has.

The game is worth full price, but it goes on sale pretty regularly and probably is right now with the summer sale on Steam.

There's also a sequel out now called Ender Magnolia. I haven't played it yet but I will eventually.

Undertale and Deltarune.

Dwarf Fortress.

Ultima 1-7 and 8 partially.

Terraria! That game is great and aged like fine wine

FALLOUT NEW VEGAS! (Side note) Oh boy, a new list of games to play as I scroll through these comments.

Ocarina of Time. I'm biased because of nostalgia, but I genuinely think it's the best game ever created. It took everything that was great about the SNES classic A Link To the Past, brought it into 3D as an early N64 game, and improved literally everything. The atmosphere, the gameplay, the story, the time mechanic, the music... It's not perfect, in fact these days it's trivial to break many things in it with glitches, but I think it's absolutely the best.

Hades

The first half of the description, combined with the unmentioned ambition of LotR, made me think of Star Citizen. But we'll have to wait another 5-10 years to find out if they manage to deliver on that ambition, and stand the test of time.

Half life and half life 2

Prumbably the Morrowind game

Minecraft

Factorio

A lot of good suggestions but my first thought was Final Fantasy X.

Baldurs Gate 3.

Without a doubt the Witcher games, and Baldur's Gate 3. Probably Dragon Age too, but I haven't played those.

There are too many to mention.

MechWarrior 2
Dragon Age: Origins
Daggerfall
Clair Obscur: Expedition 33
Baldur’s Gate 3
The Longest Journey
Dark Souls
Civilization 2 & 4
Alpha Centauri
The Outer Wilds
Fallout 1 & 2
Alien: Isolation
Super Mario Bros. 3
Death Stranding
Doom (1993)
Phasmophobia
Psychonauts
X-Com: UFO Defense
The Witcher 1 & 3
Disco Elysium

Age of Empires 2, despite being Microsoft owned, is easily one of the best strategy games of all time and has very clearly stood the test of time. It's over 25 years old and people kept playing it a lot even before the HD remakes. I remember reading that the folks that made the 1st game often had to choose between "actual history or hollywood history" for some details, often going for hollywood because it made for a more fun experience.

I suspect Factorio might stand the test of time as well, and it's clearly something made by someone who really understands the medium. I haven't begun my factory yet.