Sounds weird, but hear me out. These are games that support multiple people (often just two players) to play in the main story, but instead of the second player being a second force that’s capable of doing everything the first player can, they instead become more of an assistant to the first player. Whether that be as a secondary character following the first player around or by literally becoming a part of the main player’s move set, only one of the two people playing is getting the full experience.
Basically, the kind of cooperative play that would only really be used by a parent and their child.
Examples include:
Sonic the Hedgehog 2 - When playing in 1P mode with Sonic and Tails, a second player can choose to control Tails if a second controller is connected. (To my knowledge, this also works in S3&K, Mania, and Origins)
Super Mario Galaxy and Odyssey - Playing as Cappy or the Orange Luma to assist Mario.
Kirby and the Forgotten Land - Playing as Waddle Dee. (I love the guy but two Kirbies would be so much more fun for both players).
hitting_Gunther t1_j2cv1qh wrote
"Spiritfarer" is a pretty nice and beautiful little game with jump and run elements. The second player is a cat that can't interact as much as the main player. So that might fit your description.