I felt a lot of uncomfortable emotions watching this one. Ultimately the bug thing didn't end up making me feel as much for the characters, so while it was cool and creepy, it was hard to relate to the bug sitting back down and doing his job. Maybe if it was more established that buggys want to go outside and be free using a longer shot on the outdoor window with the prison bars, it would be easier to contrast at a glance the reality of working in a bleak office for a living.
Also, while I thoroughly enjoyed the bit where the one office worker didn't turn into a bug, I think that's partially why I can no longer related to the people turning into bugs. It kind of shuts down the idea that anybody can show who they truly are and reveals that people are just turning into bugs in real life. And I can't relate to turning into a bug in real life.
On the flip side, you animated the human expressions and movement extremely well. First I felt annoyed at that manager, then after he expressed some genuine sounding concern I had a change of heart towards him. It was cool hearing how Bill heard him. You said you had fun on the sound design? I had fun listening to the sound design too.
In summary, I enjoyed this quite a lot. While the beginning especially impressed me, employing cool sound design, relatable characters, and awesome animation, the last half felt like it had more potential and was buildup to the joke at the end instead of being a story about Bill.
For this review, I watched the animation several times over.