In the mausoleum area of the game (mid-way through) there is a golem that turns in response to the commands cut into the mimeograph (typewriter). Create a keyplate with the letters SALTATIO for an interesting effect. You may want to save the game first.
Complete the game once to unlock both Hard Mode and the Secret Room. Both will be appear on the main menu.
Instead of typing "METH", type "EMETH" at the very first card slot in the game. A different cutscene will be seen, then look on the floor in front of the door and you'll find a useful Obsidian Choker.