If you buy the upgrade from the legendary shop that allows 20 slots, then once you go back to the shop you can apply all 20 upgrades and then go back to the legendary shop and sell it, and it still lets you keep all 20 upgrades
if all the shipyards close down while there is still a boat sailing, that boat will get stranded in the ocean and it'll just keep going in circles. lol
interesting game but it gets boring and frustrating when you have to keep trying the same level over and over again because you can't find the exact right spot and moment to click