Awesome job on the game you made here :p
At first it took me a minute to figure out what I needed to do (I didn't look at the description images so my bad there), although eventually I was able to figure out where I can get my oil to transport.
I also found the cannons shooting the busses to be quite humorous, the controls are pretty good, and I like the implementation of the connection theme too!
I can see this as a fun lil multiplayer party game where you and your friends are trying to transfer the most amount of oil before all the cannons go possibly crazy.
As for polish, I would probably add a bit more drift, although I would fine tune it to be more satisfying to drive around. Add a little bit of particle animations behind your boat to add some detail. I would also clean up the tutorial a bit to make it clearer for the player. Maybe in game you can give the player a quick directive on where is the oil and where to take it too before the game starts. Just some ideas if you decide to continue the project.
Either way, I had a good time with the game! :p