Great job!
I loved the UI sound effects so much. I would recommend breaking the combo / losing life if you press the buttons in the wrong time, as one can just keep spamming them to defend every single missile.
Also, ground mechanics doesn't add too much to the gameplay, two other missiles with longer path would be better. The different missile speeds are very weird in the beginning, but as they are in sync, they do add another interesting challenge to the game.