itch.io

Sorry for the delay in replying. The key in the guard's room opens the door to the service area (the door in the lion room). There seems to be a slight translation problem here. 
As for the key to the director's room, it does exist, but it is not mandatory and is hidden in the locker room (it will be difficult to find).

Thank you very much! And you made a great video!

You're welcome! If you have any other questions, please contact me =)

If you're playing the story mode, you don't need to tranquilize the lion (the tranquilizer is for the demon). You need to summon the demon by finding and destroying its favorite item.