Hi! I thought I had sent you a review before. I really like space trade simulators and I really like yours, I have been playing for a week.
I just found a nice glitch in your game. Once you manage to have a big cargo ship and a big amount of money, you can buy expensive things and pay negative fees.
Before buying: I have 237712 credits
Then I bought 7 tons Quark Kits at 5099. The display showed -29843 credits (7*5099=35693 = 0x8B6D = -29843). I wondered if, when subtracting the value from the long int of total credits, an integer value would be used.
The following image shows the total after the operation: 237712-(-29843)= 237712+29842=2675555.
I think I can retire me now from privateering... :-)
Notice you need money enough to pay for the real price before you can start making money from this glitch.
Apart from this nice glitch, I found another bug in the part when you receive the payment from your mission for the resistance. The "%d" (or something resembling it, I can't read it with the "space font") is shown instead of the amount. I wonder if you missed a fstringf somewhere...