Nice game! The controls felt really nice and made the game fair and enjoyable. I liked the variety of enemies and the fact that you must collect points while shooting enemies.
It took me a while to see the tombstones in the map; at first I thought i was stuck for some bugs... If I had to point out something, considering that only a small portion of the environment is shown, maybe a higher contrast of static graphical elements would have helped newbie players like me ^^"
But anyway, good submission! :)