Very cool game !
It shows that you're beginning with Unity but you managed well the scope and the gameplay, with very nice feedbacks (particles, camera shake..) that's super important !
What I'll do to improve it : Make the UI responsive (using the Canvas Scaler of your main canvas), so the game windows can be easily resized. And make the Earth propeller particles follow it but not as a child, so it won't rotate with it unnaturally.