The main thing I did was design the Editors (like the Creature Creator), but I initially joined as an intern in 2001 and did some really fun divergent prototypes for Will Wright while the project was in a nascent state, and a bunch of other stuff during development.

There's a whole book to be written about Spore (but I'm done writing books for now), but the simple answer is that the difference between "hoping for" and "final" product encompasses a lot of what makes software and game development (or really any creative project for that matter) interesting. Especially when multiple people are involved. And that is part of what sparked this project, which took over a decade to research and write.

(Also, many years ago I wrote a chapter for another MIT Press book about some early Spore history. It's reproduced on this deprecated blog: http://www.levitylab.com/blog/2011/02/brief-history-of-spore...)