God, I love his reviews. He reminds me of Lewis Black, but with video games instead of politics/pop culture.
It's awesome when he can really tear into a bad game. Mentioning a game's good qualities seems to disrupt his momentum. Although, I must say that I find his reviews of (what he considers) good games to be amusing as well. It's the "OK" games that seem to discourage Yahtzee from being in top form, again because of the momentum thing. Sort of like a straight, smooth road with two or three large holes that you can't seem to avoid.
EDIT: That thing with the valkyrie(sp?) stirred something in my memory and now I remembered what it was. When I was maybe 4 or 5 years old, my dad would sometimes set up a VERY old console and he would play a game with me, or I would watch as he played a game. I don't remember exactly what the system was called (Telegames, perhaps?), but it was either a contemporary or a predecessor of the NES. One of the games my dad had for it was based on Norse mythology. I never got past the first level, which consisted of running through a stampede of caribu, and you couldn't kill the caribu or some goddess of the wilderness would shoot you with an arrow.
I suppose that just confirms what Yahtzee said about Norse mythology being a "free idea bucket."