decent enough game
but a terrible glitch... im experiencing the same thing as Naroghin... its really annoying that once ive purchased the nitrogen generator it doesn't let me switch between weapons. Its infuriating seeing as i upgraded the main weapon and then bought the nitrogen weapon just for the medal, then suddenly i have a major tactical disadvantage seeing as i can't change back.
other than that its a good game, and has awesome potential for a second one... please try your best to fix the problem.