To everybody who asks for refund, because you didn't get a game you like: Don't you think it's a little unfair to do so? You bought the mystery games with the knowledge that it is a gamble and with the list of games included, you even knew what to expect. Asking for a refund, because you don't get you're favourite game is like playing poker and asking for your money back after you've lost.
Except that poker is a game involving random chance and skill where the player's ability affects the outcomes. There is no skill involved here. Also, the Mystery games seemed to be a bit rigged. The good ones don't seem to drop as often after the initial hour or so. If it was entirely random, then everyone should be up for any titles in the pool at the same odds every time. They never tell you that certain top level games only have a few available drops.
If they felt it was underhanded or unethical to refund Mystery games for store credit, then they would have made it a point to change the rules. They haven't. Why shouldn't I take the advantage to get rid of games I don't really have an interest in buying at $3 a pop. I would much rather this had been an Insomnia sale or involved one of the previous "Build an Indie Bundle" type promotions. Something where you can take advantage of something without feeling like you were screwed. And believe you me, I have been screwed on every single Mystery game purchase over multiple sales. I see people get good Mystery games during the next sale and I forget myself and make the same mistake again. Any game in the pool of Mystery games should drop at the same rate as every other game. Make it actually fair.