The guy sitting next to me at work 'did' some of the graphics for Beneath a Steel Sky. He knew the people who thought up the idea for it. They conceived the idea in a flat at Warehouse 13 in Hull. (It is/was a big block of flats) and they let him 'colour in' a bit of the scenery for a laugh.
Aparently the whole project took over two years to write. Most of this time was spent on the AI.