At the first or second level found a throw-able weapon, 15 things, that you can sell 150 for each. So I have bought the most powerful weapon in the game, the Egypt style rail gun, and finished the game with it. I do not think i would have enough patience to do it without this feel-like-exploit. There are a lot of weapons but they are useless. The balance is just not there. I would give it ~4 but something had clicked for me in the style and my mood at that time, i have beat the game, so it is 5. ;)