Hey hey, this game is similar to the one I made Gravity Well (gotta catch enemy bullets then send them back) https://itch.io/jam/gmtk-2018/rate/299985
I like the way this one works a lot, my only complaints are the rotation speed and time before you start firing.
I think you need to rework how you determine where to move the shields to based on joystick input, it felt very slow if I just moved the stick from a side, to the center, to the other side instead of smoothly rotating it myself along the edge. In fact, if I moved the joystick to the exact opposite side the shields wouldn't rotate at all.
I also would like maybe a second more before you start firing so you can line up a shot easier, maybe have a visible indicator to show when you are getting ready to fire?