mouse to shoot, red circle is a barrel. shoot it to blow it up. what I changed: I added a acid pool, a barrel that explodes when shot and changed the map, as well as adding a health bar. it's a little glitchy though, so you have to press flag twice to load in hp bar.
thanks to @radicalace for the "borrowed" code. please like their How To:Simple Shooter Tutorial thanks to @squirrel104 for some updates