Thanks for playing and the detailed review. That helps a lot!
- You're right wrt the stiff enemies. I'm currently trying to transform the game in a more tower defense style, where you have to survive multiple waves and every enemy attacks the wall. I think this will solve this issue of some enemies just standing there.
- Actually attacking enemies are already lowering the HP, but it's not very clear. I'm going to make damage indicators to fix that.
- One of the next features is being able to increase the "circle of attack". So in that case the arrows will be shot randomly to one of the targets in it. Hopefully that solves it. I'm also considering using the scrollwheel to increase/decrease the radius. This way the player can choose to focus fire or not.