This big metal door is covered with reliefs of four animals in their lair. The door being magical the reliefs seem to be alive. All of four burrows contain some means to pull the bolts that keep the door in place. If only the animals would cooperate... Any mistakes and the door will attack and go back to normal. Breaking down the door will not work because it would just heal itself and attack back to the best of its abilities.
The one on the bottom features a horse in a fields end with a plow on the other that's attached to the bolts. If the character has no idea what he is doing (never been to a farm, has no animal lore) and touches the wrong part, the door will react. If the back is touched the door will kick out with life sized horse feet. If the front is touched in a bad way a life sized horse head will bite the hand. In order to open you need to caress the horse on the forehead to move it closer to the plow. Once there the horse collar needs to be moved on the animal and a gentle tap on the back will make him move the plow and the bolts out of the way.
The second on the bottom features a dog in the woods and a branch is connected to the bolts. First you need to become friendly with the dog or else she bites. You need to place a hand next to her and she will "sniff" it, then you can caress the head. It will then let you stoke the tummy. From this point on you can pull the branch yourself or throw a stick from the ground and the dog will try to bring you back the branch thus pulling the bolts.
Third is a snake that's tied to the bolt. Here in order to move the snake you need to grab it's tail and pull it away or grab the head from behind. For this to work you need to distract it. The snake is really fast, bites through armor and the "venom" causes small metal spikes to grow out randomly from where it managed to bite.
The final one is a big cat (tiger/panther) in a jungle setting sitting on a branch; with a cat's hand shaped lever on the other side. You need to lure it with your hand, which it will try to hunt and eat (try not to let it). After leading it through the other side, keep your hand on the lever. It will approach and leap and if you manage to get your hand out of the way it will grab the lever and it will pull it down as it's pulling itself up.
With the final bolt out of the way the door becomes fluid like a pool and you can walk through the metal.