Door set to locked, but unlocked?

[Your Computer]

No. It worked before I added the monster if I recall correctly. Both doors are locked, you find the key near the beginning and open the first door. That room leads you to another room with 2 doors, you go through the first (unlocked) door. You get to a destroyed room and you pick up a key that opens the next one in the other room. It also sets up a monster. When you get back to the room, you use the key to unlock the door leading to a kitchen.

BUT, for some reason, the kitchen door (door2) is always unlocked.

So nowhere in the code you posted is the kitchen door referenced? If so, then try not relying on the level editor and do so in the script. If not, then add conditional statements to your KeyOnDoor function. Also, for future reference, you may want to be more specific with naming your variables; that is, "key_#" and "keydoor_#" is too vague.