it's not 30 minutes, the average game is around 5-7 minutes I don't know what kind of experience this guy had but it was definitely an extreme one. Of course it depends, if you like to play really slow controling decks, the average for you will be near 12-15 minutes.

Curious what type of rewards for winners/losers in Unchained?

You get experience each game, a little bit extra for the winner and the rest depends on how many turns the game lasts (more turns more exp). Each level gives you a core pack, this is like a set of cards kinda like what Reward set is in the steem monsters. Currently, you can't trade those cards but the system to enable that is on the way. Also, those cards are pretty much the same power level of the ones you can only buy, of course, having access to both enables you better decks.

There are also extra rewards during the weekend ranked ladder and sometimes there are raffles that can give you unique prizes or you can choose to sell your raffle tickets to other people for ETH.