Windswept is wholesome, co-op, and has a demo. Please be happy.
The demo for a little 90s-inspired platformer hit Steam recently: Windswept, a pixellated platformer about a duck and a turtle going on a very large adventure while trying to get home after a storm. The platformer lets you switch between duck and turtle, or one player can take control of both characters in local co-op mode. Windswept is « coming soon, » and will run a Kickstarter (opens in new tab) soon, which I hope means it’s coming this year because I quite like it.
It’s a pretty classic setup where each of Duck and Turtle has its own has their own way of moving around—the core of a good platformer.