the bullet animation is pretty bad, the music too low and the sound effects too high, it just becomes a repetitive noise after a while.
the hit detection a bit of and the bullets seem to come from the side of the cannons at most points. also the canons / guns don't move when you do so its a little underwhelming.
also there is no indicating of level or progression. maybe instead of a heart system have the vehicle become more and more damaged? have more abilities and better reasoning as to why we are a horse drawn carriage fighting modern day cops.
its a good start but more needs to be done.