Thanks for trying out my game! I'll adjust the guards view distance and play with the settings so it takes them more time to spot you when you are crouched behind a cover. Thanks for the feedback, let me know if you have more!.

You unlock the weapons once you have completed the stealth mission category. You can also try out all the weapons in the gun range if you like. I'm also thinking about moving around the mission categories, so that you start off by doing the weapons missions before you begin on the stealth missions.