can the overlord spawn after closed doors??

if now WTF is up with dungeon 22 so mùuch doors almost no creatures to place

you can spawn anywhere in any area that has been revieled. For RTL most levels are 1 area, so yes you probably can spawn behind those closed doors. Check your map key, there are two different symbols for doors that divide areas, and doors that are in the same areas (triangle vs square on either side of the door). I do not have that level in front of me so you will need to confirm that it is all one area. Usually however in RTL the only levels that have more than 1 area are Rumor, Legendary, and the Overlords keep.

One of my favorite tactics is to use poltergeist to close a door that the hero's have just gone through spawn some beastmen behind it and then have them open the door to attack.

Brian