Really fun idea, I like the flexibility it gives you with the reloads. Seems like there would be a lot of room to expand on it with powerups or other options if you decided to go that route.
Not a huge fan of being forced to use the autoaim, missed a few shots that would have been easy to lead manually and having to press RMB to clear the target if they get stuck on the other side of a wall feels clunky vs just being able to quickly shoot the guys near you. Saw your comment about wanting it to be more tactical but it feels like it would work better as a more traditional top-down shooter.