What a beautiful job. I like the fact that you didn't add a background; this could be any time in which Dobby comes to visit or attempt to save Harry. Attempt being the key word for all but his last moments. I love the way you did his eyes, especially; they do look slightly bulging the way they should be. Aw. Dobby. *sniff*
Dobby dies by getting stabbed from a thrown knife, not a magic spell or a terrifyingly dangerous creature or wizard. Just jumps in front of a fucking knife... Here's the best part, the elf can apparate and disapparate with a snap of his fingers. He can also take others with him by holding them during.
But alas no, he didn't get to do any of that awesome shiznit in the book, just dies.