I find original but a little frustrating the mechanic of losing hearts when you shoot and double jump. After losing hearts you have to go all over the map to look for more hearts, and zombies have a lot of lifes, so you have to do this too much time in the game in my opinion. I think that with some mechanic to get hearts faster the game can really improve. Apart from that, this is a nice game. I like the pixel art, the sound and the control, so good job mate!