Very cool idea and excellent execution! The one thing I'd love to see more is to have a bit more hotkeys for things, instead of having to use Q/E to rotate, maybe rotate by have the ship looking at the mouse. Or have middle mouse button act as a "Target all" hotkey or such. That way I wouldn't have to give up full control of my ship with WASD to rotate or have to finnick with my mouse to get my turrets to target an enemy.
Those are just minor gripes though, your core is really well done! Are you planning to develop it further? I can imagine this kind of game on Steam with some more content and features. The base is very solid! Excellent job!