With so many people playing, it took nearly an hour to finish a single game. Alex won by a landslide because he managed to get a second Yahtzee later on and got the 35-point bonus in the top half of the score sheet. Claire got what she wanted too; she managed to beat Jack and Nicole.
Everyone other than her was amazed at his Yahtzee skills because they had never seen them before. He still wasn't sure why it was such a big deal but after watching the others more closely he realized that getting Yahtzees and even large straights was fairly rare.
It had nothing to do with luck for him though. He was somewhat able to calculate trajectory of where the dice would land. It didn't work every time because there was always a margin of error for these things but it worked often enough that he was usually able to get the numbers he needed.