I get the whole copyright thing but the models beings spaceships seems essential for the sci-fi style of the game(The whole jumping from sector to sector thing). Why do you need steam to sell the game? If the FTL devs won't allow you to use the sprites if you want to go on steam. I'd say just sell it without steam. Or maybe find someone who wants to make models for a space game if you NEED it to go on steam. I have to say that I am very disappointed. I guess I will look at the game but I can't say that as a submarine game I will be buying it.