I welcome skepticism and criticism for this sort of thing, and think most of it that I've seen here is well founded. But I would like to take a second to explain why I think this, and really all the progress in this area, is actually a really impressive achievement to me.
Let me try and frame this from the computers perspective. Let's assume a resolution of 1024x780. I'm not sure what size frames they actually feed their agent but it's not that important to the discussion, the point is it's a big image, and according to the article this agent is learning from pixels. So, you the computer are given let's say 1024*780 = 798720 numbers to look at. You then choose a number between 0 and 798720 (or the crazy 10^26 number the article gives as the possible number of actions at each frame) as your action for that frame, and then you get another 798720 numbers to look at. After the round is over (on average 20 minutes, if you make a decision every frame that's 20x60x60 = 72000 rounds). You get one number telling you how well you did. You repeat the process and get a new number. It's higher this time! But what is the cause? was it that click you made on frame 22456? or maybe that unlikely move you made on frame 4567?
Obviously I'm oversimplifying here, and the numbers are probably wrong. but I still think what I've said gives the right idea for what kind of task we (as a society/community/whatever) have somehow gotten a computer to solve. Computers are DUMB, the fact that it's able to play this game at all, let alone at a high level, is still a minor miracle to me.