First, a couple things about World Of Goo. World of Goo is a fantastic game that took anti-DRM people seriously, and included no DRM whatsoever. This was a perfect test of people who said they wouldn't have stolen Spore if it hadn't had DRM, that their theft was a symbolic act. It turns out that there are lots of people willing to steal World of Goo, since they ended up having a 90% piracy rate. That is to say, only 1 in 10 copies of World of Goo was purchased. This may have something to do with why the company that makes World of Goo has recently declared bankruptcy.
World of Goo does something truly impressive from a metagame standpoint, it's a fully featured game that only requires a single button. On the PC, you can play the entire game with Mouse1. I don't know of any other good game that can make that claim. (There's at least one bad one.)
I brought up this single button interface to compare to Fallout 3's less intuitive interface. Suppose you're in a menu checking your inventory, what button do you press to leave that menu? Depending on which menu you're in, you could press Tab, X, or A. To leave the Esc. menu, only hitting Esc. again will work. To make it perfectly clear, To simply exit a menu in Fallout 3, you have to hit one of four different buttons. This is terrible design. This still doesn't make the game bad, but it's another sign of how the game needed a few more rounds of polish.
Now playing: Simply Syndicated - The Right Stuff