• Divinity: Original Sin series (D:OS 1, D:OS 2)
  Excellent pair of RPGs that allows you and your partner to either work together or split up and go do your own entirely separate sidequests. Best-in-class for co-op RPG.
  
  
• Salt and Sanctuary
  Basically a 2D Dark Souls-like. There’s a bit of a procedure involved with enabling co-op for some reason, read about that here.
  

• Spelunky series (1, 2)
  Brutally hard but excellent procedurally-generated platformers. Spelunky’s pretty infamous and TBH I’m going to assume you’ve already heard of it
  
  
• Broforce
  Hilariously daft and over-the-top shooty mans action.
  
  
• Caveblazers
  Procedurally-generated platformer in a similar vein to Spelunky but with a different vibe. I personally think Spelunky is far superior, but Caveblazers can be a blast as well.
  
  
• Trine series (1, 2, 3, 4)
  Puzzle platformers where you and your partner switch between three characters with different skills. I’ve only actually played a couple of these and they were gorgeous at the time, don’t know how well they’ll have held up though.
  
  
• Guacamelee series (1, 2)
  Lucha libre-themed combo-based beat-em-up platformers.
  

• PixelJunk Shooter
  Action/puzzle game where you have to save the trapped explorers, fight enemies, and get to the exit of each level. Classic game stuff with slick controls that looks lovely
  
  
• Monaco
  Stylish heist game that usually ends in chaotic attempts to escape after a bungled mission. Lots of different possibilities opened up by combinations of different character abilities and a real good laugh.
  
  
• Magicka series (1, 2)
  Goofy wizarding with friendly fire enabled and a giant range of possible spells achieved by combining elemental effects. My partner didn’t like this so I didn’t get to play very much but it seems like a great time
  
  
• Keep Talking and Nobody Explodes
  You and your partner work together to defuse a bomb; one person looks at the screen, the other person only looks at the bomb defusing manual. You’ll want a printer for the manual and a comfortable sofa to sleep on because I’ve never seen a game so certain to cause intense heated arguments — enjoy!
  
  
• Untitled Goose Game
  
  

TACD fucked around with this message at 22:32 on Oct 3, 2021