You are on the gingafella's money when it comes to features to mark off characters you think you've discovered. It was unfortunately not added in time for the deadline. But I do kinda love that more than a few players did break out a notepad during play. It takes me back to the early days of gaming, without all the tools necessarily built in to help a player.
A shop for the money, playthroughs, and upgrades were all considered and just didn't make it in time