In original DK, it was "mostly" impossible to teleport behind locked doors.
Only "mostly" - because:
- you could possess the creature and teleport to the lair, even if it's inaccessible
- the creature will still teleport during certain tasks, ie. on payday (there is a pathfinding option used for payday and some other tasks, which allows to trace the path through doors; when door is blocking the creature, it just waits for it to open)
- this only works on locked doors belonging to you - doors belonging to enemies can be destroyed, so they are always treated as passable.
Now, I'm thinking about what the rules should be for KeeperFX.
Would it be better to leave it as it is now, or change the rules?
I started thinking about it after seeing this issue:
https://code.google.com/p/keeperfx/issues/detail?id=317
I'm not sure if teleport should be blocked by locked doors at all. After all, it's teleport - how can a door block it?
Also, creatures being able to pass locked doors in some cases adds more variety to the game, which is good.
Btw, it is now sometimes possible to pass locked doors by ghosts, but only in possession, and only if while passing it a player won't touch any wall nor floor/ceiling.