pretty cool idea, with the rotation of the shoot button like that. the only problem serious problem is that around 150/200 score it starts becoming a bit laggy and around 400 score it becomes completely unplayable. I have a feeling that perhaps your bullets are never destroyed and so the further you get into the game the more it struggles. You should preferably look at creating object pools for all of your objects, but if you didn't have time for object pooling you should at least destroy the objects so they don't persist in the scene and kill the frame rate. Other than that it was a fun game, well done :)