The "adult" and "cartoon" themes for HWY came from an interview with Andrew Heighway on Coast 2 Coast. Iirc, he mentioned these as 2 different thoughts. He mentions interest in maybe doing a cartoon theme and then says something about adult themes for playing with friends at a pub. South Park was brought up here on Pinside because Andrew also said he'd consider redoing a theme that wasn't done justice too. But that could mean any lower rated game like BTTF.