Move the mouse to aim and press to shoot. r to reload and h to heal. Be warned, you may have to reload when you start and will have to after you heal. I know it sucks, but it's because I used the most block-efficient method to program when reloading is necessary to not surpass my limit of 100.
Thanks to my friend for giving me the theme for this 100 Block challenge. Might eventually make a game with the same theme but no block limit. Have some awesome ideas. It would take a while though, as I'm currently developing the 2 most complex games i've ever created on this account and all my others. Stay tuned, one is nearly done.