For me it's Journey. That game gave me an emotional experience I've never had in any other.

How come no one has mentioned “Life is strange” yet? Also, “A plague tale”.

Bastion, Hades, Disco Elysium, Planescape: Torment, and Tyranny (even if the last act is rushed in the last two) come to mind for me

Hades

Hollow Knight

Noita

Super Metroid

Prey (2017)

DOOM (2016)

Factorio

Stardew Valley

Hotline: Miami

Beyond Good & Evil

Final Fantasy X

Celeste

Hades

Ace Combat Zero/5

Way more to choose but top of my head

Edit:

Halo

Titanfall 2

M&B: Warband

Evolve (yes I said it I’ll go to the mat over it)

Immortality

There is no "objective" when talking about subjective terms.

My personal, SUBJECTIVE favorites are Mass Effect, Titanfall 2, Subnautica, Stardew Valley, Ori and the Blind Forest, Dave the Diver, Balatro, and Portal 1 and 2

Thomas Was Alone

I've never felt so much for quadrilateral shapes.

I'm going to take this as "games that I never see anyone question their quality." (I don't even like all these games myself)

• Sonic 3 & Knuckles

• Kirby Planet Robobot

• Doom 2016

• Street Fighter III: Third Strike

• Pac-Man

• Balatro

• Steins;Gate

• The House in Fata Morgana

• Castlevania: Symphony of the Night

• Gran Turismo 4

• Mario Kart 8 Deluxe

• Mega Man X

• Mega Man X4

• Super Mario Bros. 3

• Hollow Knight

• Bloodborne

• Elden Ring

• Balder's Gate 3

Factorio, Terraria, Half-Life 2, Portal 1/2, Limbo, Night in the Woods, Lil Gator Game

Team Fortress 2

The best teamshooter game to date, endless copy cats that suck ass.

Chromehounds was the greatest mech game on shitbox 360 and you can't change my mind.

The sheer variety in player created metas was glorious to behold. Sure, you could play how the game encouraged you to play and hang your weapons in "normal" configurations. But you could also bury whole teams in indirect fire with a triple double from across the map. You could build a little punchy boi buggy with a dick piston, cockpit, wheels, and nothing else. You could even try to sweat the meta in the chicken leg howitzer or the turtle up in the armored crab.

The only limits were creativity and spacer availability lmfaooo

Clair Obscur has been the best game I've played in a long while, absolute masterpiece

Games I haven't seen mentioned yet:

• Fez - cute little 2D/3D platformer. It's amazing and very wholesome

• Stalker: Shadow of Chenrobyl - dunno what exactly is it, perhaps the settings and the grit, but it has a special place in my heart. It's about average FPS, but not too long and for me enjoyable

• F.E.A.R. - very good FPS, with amazingly scripted enemies, decent horror elements (not compulsory - you might miss some of them if you're not looking).

• Prince of Persia: Warrior Within - for me the best 3rd person action adventure ever. Best combat hands down (or head, or torso, you choose), streamlined blade dance at your fingertips. You play with your enemies, and you get many tools. There are some locked camera issues.

• Touhou: Lost branch of time - If you liked Slay the Spire, but wished for colorful mana, this is the game for you. It has anime artstyle, I usually focus on the cards, though it might turn some people off

• Dota 2 - Dunno if it was mentioned and I didn't see, but the mechanics are absolutely amazing, the things the game lets you get away with are incredible. 10/10, but other people might bring your experience down. Specially friends. Can play against custom (workshop) bots. Still takes too long to git gud. I studied the game for 10 years and still sucked.

• Divinity 2: Original Sin - also haven't seen a mention, everybody talks about BG3, I haven't yet played it, but D2:OS was also a masterpiece. Haven't played a lot of TRPGs, this was a blast, with easily set up multiplayer. Played through it twice completely, with many abandoned runs.

• CS 1.6 - remember that? I lost my childhood to that. They don't make counter strikes this good anymore.

• Synthetik - top-down rougelike shooter, with amazing weapons and physics and classes and enemies and mechanics and 2 person multiplayer

• Dwarf Fortress - the real objectively best game :D strategy simulation of the 3D box world, predecesor to both Minecraft and Terraria, but with A LOT more sand in your box. They are still extending it. And it's on Steam if you want a UI.

• Terraria (Calamity mod) - Terraria is obviously a great game, but what makes it 20/10 is the mods. Calamity specifically. Tripple the content, 5x the difficulty (20x if you try Infernum), amazing multiplayer experience. Don't install Infernum if you haven't beaten at least Revengeance on Calamity. Trust me, it will fuck you up.

• Yakuza 0 - how could I forget about this masterpiece? Story done absolutely right, that game had no business making me feel so strongly about it. Cool combat, very funny moments, but I cried during it. If you haven't tried it, check it out. You won't regret it.

• OpenTTD - Trains. Do you like to create and manage big rail systems? This is for you. And your friends. Only noobs use planes. Only psychos use boats. Nobody uses only vehicles.

Super Metroid

Doom (93) I guess ?

Also HL and HL2

Age of Empires 2 /w The Conquers expansion pack.

Roller Coaster Tycoon 1. (2 was weaker without OpenRCT2, the real masterpiece, but idk if unfinished projects should count or not)

Quake 3 Arena, Unreal Tournament 1999 GOTY, Worms Armageddon, SimCity 3000 Unlimited, Forza Horizon 2 / Motorsport 3, Need for Speed Underground 1, Clonk! Rage, Metal Gear Solid 1/2/3, Ace Combat 4, Okami, Tokyo Jungle, Zelda BOTW, Mario Odyssey, Sven Co-Op, Killing Floor 1, Final Fantasy 7, LISA: The Painful, Everhood 1, Deus Ex 1, Left 4 Dead 1/2, Portal 2, Battlefield Bad Company 2... Champions of Norrath and Return to Arms, Diablo 1, Baldur's Gate 3 makes the list...NIER both games. Planet MiniGolf.

I could go on and on.

Video:
Doom

Tetris

Chrono Trigger

Table top: Chess

Magic: the Gathering

Everdell

Azul

Curious to hear what the criteria for "masterpiece" is, otherwise I think it is just peoples' subjective opinion of what makes a great game that they also think others might agree about being a great game. Genuinely curious, interested in discussion, not saying this to shut down any of the answers here.

Psychonauts 1 and 2.

Some of the most imaginative big budget games in existence, from themes to art style to level design

Nethack

Inside.

Prey, System Shock 2, Outer Wilds, and Undertale are fully-realized microcosms where the primary game is unfolding the complex origami of the setting. All of them absolutely beautiful to experience.

Hollow Knight is peak