Love the pixelart, nice looking game, the laser was really satisfying.
It was a bit hard to understand the impact of the upgrades, could not really tell / fell the difference even with the text explaining it. Also I ahve 2 monitor and the mouse would go out in my second screen and clicking would make me lose control of the game, most of the time leading to my death :'(
That being said the art is great, nice use of few colors, the main character and the enemies sprite animation were great and those blood splatter were really cool.