You can press C to go prone and because it puts your hitbox underneath the floor you become invincible. Besides that you can pick up some Mountain Dew® or Doritos® as you're running to restore your helth hp. Next to the explosive in the first big room is a good place for it.

Sure, you can bind the keys however you want. That kind of thing tends to get banned only if it's an emulator doing something the original system couldn't.