I think that if derpy dives fast enough from a big enough height she breaks the sound barrier when she hits the water and there is a sonic derp which is a giant sonic boom of muffins
Under water is cool and I think you pretty much hit the mark on backdrop for this one, but Derpy's lower anatomy needs work(wheres her lower back? is her legs bending weird or is it me?).
dermazed
BTW check out my journal entry about an EQD AJ Appreciation Drawfriend. There is still time to get something in if you're interested in contributing!