I like the gameplay here. 

I only wish it had music. If I was doing it, I would have something tense and driving, that got more muffled, slightly quieter/ distorted when you hold down the shift key.  Create a track, and then run it through some distortion (specifically a low pass filter and maybe some extra reverb) and add in a heartbeat sound so now you have two tracks to fade between when shift is pressed.  

on a related note, I just recently listened to the Dunkirk soundtrack. 

Let me know if you want to collaborate, or if you are happy with the game as-is

There is so much here! I really appreciate how many different mechanics you successfully wove into 20 seconds of gameplay! Procedural objectives, wind, bullet drop, breath-controlled scope swaying, etc. The result is a truly immersive simulation! I would absolutely play a longer version of this game. 

The colors all complemented each other, and the art was fantastic - clear and cute without distracting from gameplay.

I noticed that the crosshair could not reach the edges of the screen. Is this intentional? What happens if your target wanders off-screen? Do they appear elsewhere? Or have you blown your window of opportunity?