A door in the Underworld is physically modeled out as a heavy wood or metal object attached to pivoting hinges, optionally with a locking mechanism. Doors have parameters for physical strength, resistance to fire damage, resistance to magic, their acoustic blocking factor, strength and complexity of any lock. What does this mean for when a player encounters a door?
* Player might smash through weaker doors. If door is susceptible to fire, they might burn it to weaken it, then smash through.
* Could pick the lock, or possibly smash the lock.
* Might spike the door closed to prevent a creature from opening it from the other side.
* Could listen at the door to try to hear what's moving around on the other side.
* Use magic spell to unlock and open the door; or use magic to bind the door and block it closed.
<...>
What is interesting about this type of simulation approach is as a player I just have a problem to solve or have a goal to achieve. I don't have to think about what the developer wants me to do. I don't have to worry about the 'right' thing to do. I might solve it simply, or go for a complex or challenging solution. Honestly both can be extremely rewarding.
This level of physical simulation is quite rare for RPG games