Nice first attempt! I recommend reviewing the story first and potentially rewriting parts that are a little awkward to read out loud. Your voice is a good fit for audiobooks and with practice the monotonous intonation will fade.
Also, if you work with, or start working with editing software more, you can shift the pitch and length of the "long, low belch" a bit. Right now that doesn't line up.
But yeah, I'm still rock hard while listening to this thing, so the essence is very impressive! Can't wait to hear you do more of these! :]