And not even that but unloading with less than a second after spinning around from facing the other way? It actually puts Legolas to shame.

The previous video did a time comparison. He shot 7 targets to Legolas' 6. In this video he's noticeably faster.

Well, and they CGI'd the most of the movie's Legolas' "arrows" as well.

http://www.kotaku.com.au/2014/06/game-of-thrones-has-cgi-in-...

Every arrow fired on Arrow is CGI due to crew and actor safety.

A second's quite a long time. Depending on the weight of the bows he's using, a quick, explosive release might be the only way he can actually put enough energy into the bow to get a shot off at all.

I wouldn't worry about his bow weight. The trajectory of his arrow on one of outdoor shots show he is not even shooting 30 lbs. You can hold that as long as you want.

i wonder what happen when he fails

We just saw the time it worked. And he had a big grin on his face. How many times did it fail?

One of the potential failure modes is getting hit with a arrow, so even failures are impressive.

Probably quite a few, but what's your point? That he shot enough arrows that it eventually hit without requiring significant skill? I tend to believe his success is above that of chance.

The actual odds are not really that important as what you really care about is not the odds that that specific odd thing happen but how many odd things happen given enough time.

One of the more amusing examples was Ripley(sp?) from the 3rd Alien movie does a long distance one handed backward basketball shot that they were going to use CGI on. The funny thing is watching the movie you see very honest surprised emotions which seem almost to believable.

However, the actress actually made the shot during the take which is why all the actors have a much more believable WTF expression than normal. The only thing out of place is the actress expression where she must have been trying really hard not to blow the take.

Edit: https://www.youtube.com/watch?v=rOrTfA8QZyI 4:35

Anyway, my point was if she missed then nobody would have thought it odd. They were not going to try again until it happened, but once it did happen they wanted to use that 'good luck'. It’s sort of the best take effect, walk around and take 1,000 pictures and the chances are something unusual happens in that shot. The odds of that specific unusual thing happening are not high, but the odds of some unusual thing happening is.