I bought it mainly off of the amazing artstyle and GAFfers' recommendations. Are there any other good couch multiplayer games? I'd specifically love ones with good co-op.
This is my list of games in my KING OF THE COUCH group on steam. Mind you, most of these are competitive, and i'll note when its co-op specifically:
Castle Crashers (Co-op Beat 'em up, 4 players)
Crawl (4-player, Competitive, very awesome!)
Dungeons: Eyes of Draconus (3-Player Co-Op Beat 'em up, its only ok, wait for sale, but its mindless)
Lethal League (4-Player, Competitive, Pong+Jet Set Aesthetic+Some Fighting Game Mentality. Comes out tomorrow, gonna be great)
Mega Coin Squad (4-Player, Comeptitive, 2D Arena-esque game, really good party game)
Mercenary Kings (4-Player Co-op, like Borderlands, lots of style, the substance not so much. Very grind-y. Again, wait for sale, but its not bad, just not great)
Metal Slug 3 (2-Player Co-op. Absolutely get this when it goes on sale again)
Monaco (4-Player Co-op, work as a team to do heists, very unique art-style, pretty fun, can be had for cheap during sales!)
Mount Your Friends (4-player Competitive. Just check the Steam Page. You'll know if you want it from that. Very fun game though, also solid for hang-outs/parties)
Niddhogg (Already talked about!)
Speedrunners (Mentioned already, but really fun racing game. Easy to learn, hard to master, sure to ruin friendships)
Spelunky(4-Player Co-op. Dungeon Crawler, really fun, but can be pretty difficult at times, so if you want something easy-going, maybe turn elsewhere. Very fun though).
The Yhawg (4-player Co-op/Competitive. Its hard to explain the Yhawg, but nab it for 5 bucks or lower. You'll probably only get a couple hours out of it, but its pretty neat for those couple of hours).
I left off all my fighting games, but there are plenty of those.