I decided to remake one of my favorite games, Besiege, in as little time as possible. It ended up taking around 2 weeks to get where I am now and I was able to make some modifications that I would like to see in the real game.
What I learned
I learned about the nuances of the PhysX system which Unity uses for physics. I learned about how the various settings make a big difference in performance as well as the physics simulation. Aside from that, I learned how to make an in-game building system to create rigid bodied machines.