Oh deery me

I can't say much on the animation. Overall, it looks rather clean to me. :> I don't see the 'jump' with the front legs, but if you do, and acknowledge it, then that's alright. I will comment, however, on the deer's anatomy and fleeing/jumping/running behavior.

First thing that jumped out at me was the tail. It seems to wag up and down, and by the shape of it I'm assuming this is a whitetail, it would be stiffly held upwards in a 'flagging' position. Next, would be the bobbing head. Now, if it was merely jumping from a standing position over something, the head would bob just a little (think horse jumping), but with the way you've got it I'm assuming it's bounding/fleeing and the head would be upright, just like the tail. There is a six-second shot of a whitetail flee-jumping on Youtube (I can't copy/paste here, though I don't know why) "Deer Making Long Leaps". It illustrates my point exactly.

Next up is anatomy. I really don't have much to say for this, since it's a simple lineart sketch, but it looks pretty good. :> One thing that sticks out is the stomach/abdomen. When the legs contract on the impact/take-off, you have it's stomach contracting upwards into the ribcage and toward the spine. Physically, it can't do that. Think of it as something being squished. both the stomach and the spine will bow outwards a bit. Not as much as the spine will with the stomach, but just a little.

Hope that helps a little bit :>