It's a lot of fun to fire, it makes a great sound.
Interesting note, if I charge up the pneumatic chamber a second time without adding fuel and fire it, it makes another fireball about 1/4 the size, JUST using remnant fuel from the first shot.
When I get moved into my new house, I think I'll try making a device to expand the flame so it ignites more of the fuel, also maybe a spring loaded cap to prevent the fire in the barrel (that you can see me trying to blow out in the video)