Good arcade game.

It would be nice if there were some arrows (or exclamation marks) to the left and right of the screen which flash, so the player knows when some bullets are going to appear; currently, it's very easy to get caught off guard and be unable to outrun the bullets.

Quite good!

I think that there should be a button to end the round instantly, since a lot of my time was spent waiting for the countdown to finish (even in the later rounds). Alternatively, you could make the round end automatically when you get the correct combination.

I feel like the concept could be taken further with different shapes, moving numbers, or different labels (words, equations, colours, etc.), because right now the game feels a little bit plain.

I think that the music and art fits the game, so good job!

Sounds like a Passenger of Shit song if he were to produce Melodic Dubstep.