i think your metal frame needs to be a darker iron look, right now it looks as though if i sneezed it will disintegrate from too much rust. if this door is supposed to exist in the medieval time period then it wouldn't already be rusted to bits. metal doesn't rust that fast and the door would be >20 years old.
You might be able to lower the poly count by removing some edge loops that run along the curves of the locking bolts and handle. For something that probably wont be moving, and if they do move, the player won't be 2 inches from it, smoothing groups will help create the illusion it's more curved than it really is. If they…