About the map, if you try building a map... you actually can make something from it, and have your own piece of map (like on a sheet of paper). That is intentional.
The keys, yes, it is a very great idea.
Enemies, It's not fitting, traps would be great though, enemies will leave a HUGE suggestion to the player that the player is in a new room, rather than just, walking around the rooms the player already explored.
Its just not supposed to be a rogue like with just killings...