Thanks for the feedback! Especially the camera controls.
On the fuel topic, I wanted to add some more strategic elements to the menu screens and it seemed the easiest way. I plan to have some "special encounters" when you run out of fuel. Just as in real life, someone will sense your need and want to take advantage of the situation. In other words, you will have to give up something of value in order to get more.
Planning to also add a sub "health" meter and some encounters will lead to damage or repair of the sub.