You can buy Magic Keys here for locked doors. The game has a total of 13 locked doors: 2 in Castle Argus, 4 in Goldor Manor and 7 in Temple of Time, as well as one free key in Dwarven Hollows.
A hidden room in the tavern has an NPC that lets you check your bestiary and a few other game statistics, including open chest percentage.
Before [Castle Hein]: 35% chests, bestiary 1-65, 71-74
After [Castle Hein]: 39% chests, bestiary 32%, 1-74 + bosses