Assuming Steam?

• Halo, obviously. Master Chief Collection is pretty cheap to pick up these days, don’t miss out on the Halo 3 ODST DLC.

• Ready Or Not can be a challenge with just two people, but it is very rewarding to get a good score.

• Zero Hour is very similar to Ready Or Not, but it has different features and I find it a bit easier.

• Deep Rock Galactic

• Risk of Rain 2

• Elden Ring (Seamless Coop Mod is highly recommended)

• Monster Hunter World (include Iceborn DLC)

• Generation Zero

• Project Zomboid (if you like this one you’ll probably sink hundreds of hours into it)

• theHunter Call of the Wild (chill hunting shooter)

• Farming Simulator 2019 (new ones may be better, haven’t researched)

• Barotrauma

• Factorio

• Elite Dangerous

• Green Hell

• The Forest

• Sons of the Forest

• Morrowind has an OpenMW fork that supports multiplayer, if you get it set up this can be a fun game to play

My wife who is a huge Minecraft fan has been playing stardew valley with me.

She also loves the portal 2 coop

Project Zomboid. Feels like a Sims game with zombie and great survival elements. Arguably, the best zombie survival game to hit the market. Supports split screen couch co-op.

Abiotic Factor has been really fun for my buddy and me. Especially with the new update that came out last week. It’s a Half Life themed survival game.

Others that get my vote:

Valheim - Norse mythology themed survival game with Playstationesque graphics

Phasmophobia - THE ghost hunting game(see also Ghost Exile, Ghost Exorcism Inc., Forewarned)

Left 4 Dead - the original Zombie FPS series (see also Back 4 Blood, it’s kinda alright) PILLS HERE!

Risk of Rain - Pretty tough shooter series

Stardew Valley - A modern Harvest Moon, farming/life sim

Don’t Starve Together - If you played Stardew valley in hell, but everyone’s name started with a W

Factorio/Satisfactory - Resource harvesting and logistics sims. One’s isometric, ones first person, one has zerg rushes

Grounded - Honey I Shrunk The Kids: the survival game

Deep Rock Galactic - Left 4 Dead for Dwarves. ROCK AND STONE!!!

Overcooked - cooking and serving game, lots of communication required

Portal 2 - First person puzzle game, also lots of communication required

Barotrauma - Submarine sim on Europa, requires marriage levels of communication

Binding of Isaac - Roguelike shooter that’s sort of Zelda inspired, multiplayer was a little janky last time I tried it, but that was a while ago

The Forest - Excellent horror survival series

Starbound - Terraria in space

Trine series - A modern Lost Vikings, side scrolling puzzles and platforming

Subnautica 2 - A beautiful and terrifying diving/exploration game, original game has a coop mod 8 years in development, but it’s been very buggy

Diablo - First and second games are still very solid experiences and there are some excellent mods out for both

Escape Simulator - Literally an escape room simulator. Has workshop support on steam for even more puzzles.

Green Hell - The Forest, but in the jungle, much more focus on the reality of being stranded in a place where just about everything is likely to kill you.

No Man’s Sky - Space/planetary exploration sim

Dead Island - another zombie FPS

Dying Light - a zombie game with parkour

20XX/30XX - Megaman X styled platformers with roguelite elements

GTFO - Extremely hard, stealth based, alien FPS

Most “Souls” games - Very fun coop summoning, if you don’t mind the sometimes extreme difficulty

Goat Simulator series - Goofy exploration games

Magicka series - Isometric action adventure games where you combine different elements to cast spells

Barony - a true roguelike FPS RPG, voxel based, very hard

Void Crew - Space sim, mission based, sort of Egyptian mythos themed, meant for up to 4 players but definitely possible with just 2

Human Fall Flat - Puzzle/exploration game

Half Dead series - Cube: the game

Orcs Must Die series - Tower defense

Dungeon Defenders series - also tower defense, but with class based

Secret of Mana - One of the first action JRPGS, the remake has drop in coop just like the original, but I believe it’s couch coop, so if you’re not right next to each other, you’ll need something like Parsec to play it

Have a ton more, but those are the ones I can recall having the most fun. Others have probably listed a bunch of them and I probably missed a few good ones, but hopefully a few of them are new.

You could always tinker with some emulators for some retro coop games!

You can play Stardew Valley in multiplayer co-op mode, it’s also quite cheap at $14, it’s available on every platform and even has excellent Linux support

I haven’t seen Rayman Legends mentioned, so I’ll throw it out there. It’s a pretty flawless game for what it tries to be, and it’s a lot of fun to play with a friend. The musical levels are just extraordinarily crafted. Definitely recommended if you’re into platforming at all (and even if you’re not it’s worth a shot!)

A couple titles that deserve mention and I don’t see in any other lists:

Children of Mora - Narrative driven action RPG with some light Roguelite-ish elements. Amazing world building and story telling, good character choice/building and gameplay.

Cassette Beasts - Pokemon, if it were good. Much more mature story, tons of quality of life systems that makes building things fun, a weakness system that matters a lot more than “number big” and the entire game is double battles. I’ve played the game start-to-finish in couch co-op and it was incredible. They’ve recently added online multiplayer, but I cannot say with 100% certainty that the online allows you to engage with the story together. Couch co-op has one player play as the companion character in an otherwise unchanged experience whereas online has one player character hop into another player characters world.

Weird enough, the Monster Hunter franchise - I’m not sure how this isn’t anywhere else in this thread. Use large weapon to hunt large monster. Build bigger weapon to hunt bigger monster. World and Rise are both on sale on Steam right now. World is dumb to move through the story together though, despite the fact that most fans who aren’t me are likely to call it the better game.

A few I’ve played with a friend of mine: the We Were Here series, Portal 2, Monster Hunter World, Factorio and Deep Rock Galactic (which we both didn’t like, but it’s pretty popular)