I'm going to agree with Filarius on the sound issues, some things are too loud. As well as equalizing the sound effects, some low key, generic background music throughout the first half would help it seem less empty.
That being said, I think the sounds effects themselves were well timed, as was the humor.
The artwork got it's point across.
But more backgrounds, smother lines, characters with bodies/cloths are all things that might help improve/draw a larger audience to your animations.

NOT so bad.
You need normalize sound volume, it is jumps too high. In case sound at end you (may be) use as screamer, sound of beep while kid is thinking - unnecessary high