I manage to play your game with a high score of 5 kills in 30 seconds. The game reminds me a little of the classic arcade game called Smash TV. However, I do have some suggestion for your game. First add in swarm of enemies to appear on screen to increase the challenge. Next have the mission to collect multiple of weapons like the machine gun that auto fire, the spread that fire ten bullets, mega bomb were the radius of bomb cover the area, flame thrower and more. That way you can collect weapon, but interchange them as an advantage during the game. Finally, add in an option to allow the player to change the control buttons. I hope these suggestions would help improve your game.