The right door key can be found in level 15 where you see that relic. To reach zombie girl enter the ruins and find a statue pointing at the roof. Find a ledge to grab onto and you are good to go.
There will be a sexy bunny costume(from polls on YouTube) that will have different animation for a single enemy and will use a mallet instead of her pickax. Although since there are a lot of frames to draw it will be after v.1.0.