Reminds me of a mix on Hotline Miami x Stickman Sniper Elite.
Concept is strong, but the game feel is not quite right yet. Feel like the link of movement to mouse while strong is currently making attacking feel a bit floaty and not easy to control.
Could be you click and drag to aim and fire, but that keeps your player locked in place? Wouldn't stress too much around limited bullets either, could be unlimited (keeping the reload though, as makes fun wait times between being able to attack).
Definitely would record how long it takes to beat a level so players can try for better times.