Nothing, apparently. From the devs: First things first, we’ve made the decision to make Retrograde Arena a Free to Play title. The most important thing is that EVERYONE who purchased Retrograde Arena before now will be given a full refund. Thank you so much for your support but the last thing we want to do is have anyone feel cheated! There’s been a little bit of a hiccup on Steam’s backend but we expect everything to up and running by 10AM PST time!

Oh, my God, I didn't know it would be like this. I just want to give the rest of the keys to you. I don't want to waste them. I'm very sorry