THANK YOU, finally someone who gets derpy's voice the way I imagined it. The one in the actual show is just an abomination. The writing wasn't as clever as some Dr. Whooves podcast I ran across on youtube about the tardis crashing into Twi's library and scary stone pegasus weeping angels attack them when they blink (still funny though). But the character animation is still spot on, almost identical to the style of the show. The directing could be improved though, the whole thing is in one boring location cutting back and forth. Just a more interesting background would have helped a ton, . The sonic screw driver looked way too detailed compared to everything else. Think of it like how you could draw a detailed apple and it would totally look like an apple, but compared to what's in the show, apples are just a one color red shape with a brown stem poking out. They're extremely simplified. Just study the background objects like pies, bails of hay, rope, butterflies, clouds, etc. See how they're all much more simplified than the screw driver. Back to the backgrounds, you almost never see a shot in the show where the horizon is that high, and the sky is just one color. If you would add in just a simple cloud that moves slowly/subtly in the background. Maybe a bird could fly out of a tree or something (since they're in the background). Speaking of the trees, those are another thing you put too much detail on, they don't match the show. For how well you replicated the character animation background elements stand out as pretty poor in contrast.
Doc's voice is a little boomier/louder than Derps and it has a few peaks where it gets in the red, and the music at the beginning is a touch too loud. Spend some more time doing the audio mastering, making sure everything meshes well together. There's no noise or anything, the individual tracks are all fine, they just need to work better together.
Keep up pacing, it seems to drag a little. Look at the amount of zip-lines used in the actual show, the cuts back and forth feel bouncier and less dry and more in time with the music.
Anyways, those are all areas you can improve in, but it's still really good. 20 out of 5 stars