The game is out, and completely free. However, a bit later down the line (in a week or two) there will be a small piece of DLC, known as the Goodie Bag. It includes a little bonus mini-game with multiple stages and an Easter Egg room in the game itself, the soundtrack, art collection, and if we manage to get it to work out, will also be what makes Trading Cards available if you own it. It's mainly for anyone who would want to support the game.
Until then, I hope you all enjoy the game well enough.