I'll highly recommend Untangled 2. It's a platformer based around two-player couch co-op. I played it on the Nintendo Switch and found that it was cheap (~$5),

I'll highly recommend Untangled 2. It's a platformer based around two-player couch co-op. I played it on the Nintendo Switch and found that it was cheap (~$5), had excellent platforming mechanics, and very clever puzzles that were very different from any other game without being too hard or frustrating. It's relaxed, beautiful, tons of fun to play, and exactly the kind of game to play with an inexperienced co-pilot.