Yes I agree, With more playtesting I think we would increase the quality of a game feel.
Currently red zone not only increases projectile speed. It affects movement speed, attack speed, regeneration speed and projectiles speed for both for you and enemies.
Maybe we could also affect player accuracy, make him stop/speed up infinitely, maybe make move speed not affected, maybe add a timer that starts damaging you if you spend too much time in one zone (cheap trick).
I feel there are plenty of room for improvement.