Developed by Might and Delight, the creators of Shelter, Pid is currently free for any one who subscribes to Bundle Stars. To subscribe you must sign in through your Steam account and supply an email for the code to be sent to. Bundle stars is a CD-key website that offers discounts to compete with many in the same market.
Pid is an action adventure 2D platformer, that features co-op play, beautiful graphics and a surreal environment, and a rich story… Plus it’s free. There was only 10000 or so codes when this was posted, so be quick.