This game is very well made, but I did have the exact same issue that cyberleon pointed out. I spent all my money in the early game thinking that that was what I was meant to do. It gave me the option, so I assumed that I would get my money back. But I didn't, and I had to start selling units, which did not feel good. But even after selling units, I could not get enough money back and I got annoyed and quit. I might try and restart knowing not to buy every unit, but I think buying every unit you can should not really be an option if it is this punishing in the beginning.