you use W A S D to move SPACE to jump and 0 (number) to shoot the thing that is down on the screen is your HP, out as 4 blocks=4 HP the numbers that appear on the top of the screen is the boss HP, as a number 300, this is a work-in-progress, all sounds, effects and images were created and generated by Bfxr, except the menu song that is originally from the Scratch gallery and the static sound on the screen that is from a youtube video, there's a lot more to add, such as levels and score points, and maybe some story
i made this on a little bit more than 1 day, and i hope it gets noticed and that it's get out of the (work-in-progress) mark. i recommend you to download the project if you have scratch offline editor for way higher performance.