Great game, but it feels a bit unfinished. I liked the character design and music. The menu and character selection screen also look awesome!
As for throwing stuff at the enemies, I think it would feel better if there were some feedback if I hit or missed.I managed to beat the game once but I didn't even realize that I actually overloaded someone, it's difficult to notice.
Also, I don't see why should we overload these little boats with cargo, they're just minding their business and aren't hurting anyone. If you had to dodge their attacks, I think it would make the game more fun.
I found it hillarious that when you jump, all the other ships jump, too.
Overall, I liked the game: it's colorful and funny. Great job!