I can’t say enough how much I love Psychonauts. I hope you get the chance to play it. Here’s concept art for the level called The Milkman Conspiracy, which involves poorly disguisedG-men, little girls selling cookies, and The Milkman. Oh, and the level is full of warped roads that fold back on themselves. And a Crazy Den Mother.
Double Fine has been very generous with their concept art. You can see loads more at doublefine.tumblr.com.