Very creepy and sad, that why I like this! I don't have much to say about this. The metal of her heart it's very well done. It looks like a very well oiled machine. A cold heart. Her expression is very apathic with a mix of sadness. I would just correct a little thing, one of her eyes looks a bit bigger that the other. But it's nothing very exagerated! ^^
As for the rest. The simple and rusty background constrasts perfectly with her perfect metal heart. Lovely!