Here's the same PPT shrunk to just under 7 mb. Pictures might be slightly reduced in quality.

Most of the size reduction is from compressing the audio.

When you use PPT's option for animation sound enhancements, the file has to be a wav (uncompressed, large).
When you instead do "insert->audio", you can insert aac(m4a), mp3, wav, and others. Doing it this way, you can get something much smaller at the same quality.

:)