Wow! I really enjoyed this gameplay, very intense for me that don't play any FPS a long time. I prefer to run away until get a bit of confidence to shoot some opponents LOL. I believe that fastest shootings will improve the player experience because they were taking a while to hit the target. Maybe was the best way to implement the mechanics because of the deadline. I never developed a FPS, but Physics.Raycast will help you to calculate the shooting collision with the Game Objects. Just to clarify, the Raycast will detect any objects that intersect a line. This is all, good job, bro! :D