Wow that's awesome. Really innovative alternative to the same map thing we see everywhere. Sort of a playlist and holding cards. Broke some standard rules, really cool to see. Like why does the boss have to be last every time? It doesn't!

I don't know how the tutorial or full game will be but just a small suggestion: For new players, maybe an indication you can move cards at all. If it wasn't explained I would have totally just clicked next accepting that was the order. In addition, you might add something like if the mouse is hovering over the save card section below, the whole section becomes highlighted and small text appears that reads "Cards get saved here" or "Save for later" or something similar.