Very fun for a first game! I enjoyed it quite a bit. A quick improvement would be to show more information on screen: what is my current speed? How much will this increase my speed? How much does this upgrade cost? And also graying or crossing out upgrades if I can't buy them anymore (like getting rid of the left button once it's been used).
I had fun with this, some nice audio and the stuff I mentioned above and it'd be even better. Thank you for the game!