Your stuff isn’t bad. It does need tightening up in a few areas.
First, loosen up Charlie a little. He tends to have his back and neck ramrod-straight most of the time… give him a little more play in the spine, especially when he’s engaged in dynamic behaviours like getting ready to jump over the waterfall.
Second, pay attention to where your characters’ limbs interact with the environment. In the scene where the dryad leaps onscreen and then from tree to tree, his hands and feet never have solid contact with anything: he drifts and slips all over the place.
The physics in your animations isn’t as realistic as I think it needs to be. Do some careful study and analysis of how objects bounce, fly through the air, land, etc. When the dryad jumps from tree to tree, he’s moving much too slowly for it to be believable. To make a jump like that, a character has to really hurl himself forward. Remember, everything behaves the same in flight, whether it’s a basketball or a dryad. Imagine how quickly, hard, and high you’d have to throw a basketball from that first tree in order to hit the second. Your dryad should follow the same trajectory.
On that note… in the scene where Charlie slams into the brick wall, it’s very unbelievable to have the bricks slowly slide back after the impact. Huge chunks of stone like that would move during the impact, and then stop immediately–they wouldn’t continue to slide after Charlie had fallen off.
Finally, check your timing–it feels a little slow to me. Depending on how you’re pacing your story, we really might not need to see Charlie take six slow steps down the path before the dryad makes his appearance. Don’t be afraid to put real zip and snap into your CG animation, just the same way you’d put it into your classical stuff. In my opinion, a lot of CG falls prey to moving too slowly: because the artists don’t have to draw every frame by hand anymore, they lose the sense of efficiency and economy that classical animation forces on them. 
Of course, timing issues really can only be checked when the scenes are edited together; I’m just flagging something that I think might become an issue for you.
Despite all these criticisms, I really think the work is good. As I said, it just needs to be tightened up to really make it come alive.
Good luck.
-Steve