How did I win without killing my opponent?

I'm a little confused. I was playing a game with 3 bots, two had been eliminated, and it was down to just me and one last robot. We were both using the same deck (Ajani), and gaining life like mad. I got him down to about 10 when he planeswalked, there was a chaotic reshuffling of everything, and he bounced back to around 80, and one of his creatures was at 65/65.

He doesn't attack (though he should have) because I had a 47/47 creature, and a bunch of moderate units (3 or 4 around 6/6, and 3 or 4 around 2/2), and ends his turn. At that point, because of the plainswalk and the chaos, it starts counting like mad. I was at roughly 200 health, and my 47/47 guy was just starting to get all of his increments from all of my health and the other creatures. However, at this point, during my turn, while it was adding to my life during the start phase, and powering up all my creatures, it tells me I won. It doesn't even get through the end of the start phase before it does it. I got 2 achievements for it, but nothing indicating why I might have won. My stats page now lists my highest life total at 224 (which is what it was when it stopped), and my highest power creature at 47.

Now I know at least two of the win conditions, but neither make sense here. The first being my opponent had 0 life, but I wasn't doing any damage, so that can't be the case. The second is if they run out of cards, but they weren't drawing any cards and still had probably 15 or so left.

So, the tl;dr version. What are the different win conditions in the game? Did I just hit a glitch, or is there some way I could have won during my start phase that I just don't know about?