An update would be nice, also the double click to shoot thing is very weird. If you shoot once and try to shoot once more too soon it will cancel the next shot as if it happened. It would be nicer if it was click to shoot with a cooldown of 0.2s or something instead. The double click is very inconsistent at least for me.
You could add more levels, another boss, vertical levels or enemies with some other attack like shooting tre shots at the same time or burst firing. :)