I've just added 100+ secrets, big and small, to the Hop's Iconic Cap DLC. New features, new jokes, new conversations, new music, new minigames, ranging in obscurity from "can't miss it" to "break out the decompiler."
In addition, I've added 30 Steam Achievements. 10 are available in the base game and 20 require the DLC. Most of them require doing unusual things and they all have hidden descriptions, so consider the achievement names and images to be your clues.
Buy Hop's Iconic Cap here! Happy hunting!