I adore the use of color and the graphic design here. Little details like the tilted boxes add so much charm.
The first Adventure Hook provided is absolutely genius. I was thinking it reminded me of Psychonauts, then I saw the direct reference in the Death Within the Mind section - you channeled that inspiration perfectly here.
Because, it's so different than other adventures its a lot of content for a GM to digest (sometimes literally), but the way it's written and presented makes it fun to do so. I struggle to decide if I'd run it as is or harvest it for ideas - in either case, it's super useful!
The D66 Valuable Treasures on the last page would be interesting to drop in any adventure, I like the madness of it.