Argh! What the hell? I finally beat the thing, and then... it crashes. Without spoiling anything, it crashes just as the music starts to play. Replayed the final "thingy" three times now, and each time the same result. I'm assuming* this is because Valve couldn't possibly top the Still Alive theme and instead of having to write an end sequence with an even better song the game simply crashes. I mean, who finishes these things anyway? Bah.
*I may be wrong about that. It could actually be due to the video that starts to play, which my ageing PC has been known to have problems with.