I have not tested them on the Deck, but the We Were Here series of games is great two-player puzzle-solving fun. At least the latest titles are Deck-verified, not sure about the older ones. You can play them in any order you wish - although I’d leave Forever as the last one to be played.

It Takes Two is another brilliant two-player adventure puzzle game. Only one person needs to buy it, the other can download the friend pass to play (although you get achievements only if you buy the game).