Audio: I have no idea if the the audio was compressed during rendering, or what your settings were. I'd recommend however that if you're not already, you use clipconverter(dot)cc or similar to grab a .wav version of the audio. It even lets you set the start and end times so you won't have to download the whole audio file. From there, keep the wav file and work with a conversion to mp3 if need be. After all is said and done, drop the wav in the final render.
Animation: There were a few stand out drawings that show you have more ability than you're letting on. I'd like to see that same ability reflected across the board for future animations. Expressions are good and readable for the most part. Boob physics were present.
I'd recommend pushing the contrast on the outlines as opposed to the fill for certain characters. Specifically, the blues and purples. When you used the "white of the eyes" I could read everything; as soon as you went back to using the outline colour for the eyes, lost that crucial immediate read.
Keep on pushing, and don't worry about how long or quickly you complete them. Any progress is progress, and you're already showing good potential.