As you have done this from an isometric perspective, the black pixel on the left hand side of where the key goes in, needs to go up one space.
It's a great start though :D
Oh, those are supposed to be like those, border gold bar thingies they have around the edge ;o. I don't know who I would have done it ;n;.
cool, just put some shades on the outline. or just remove it... I think. anyone pixelate with the same style. 
;o, Thank you for the tip and feedback! Much appreciated ;D