I don't recall ever playing a game that was quite as family-friendly while also as cooperatively-focused and challenging as Putty Pals. You'll need to work together either controlling each pal independently yourself (this gets challenging as you get deeper into the game) or with the help of a friend. Making clever use of a relatively restricted set of moves you'll be jumping, swinging, and bouncing together through each level and if you're up for a challenge unlocked zones and speed run modes crank up the difficulty for more experienced pairs as well.