A combustible or explosive element is an element in Powder Game and Powder Game 2 that explodes on contact with a lighter element.
Explosions[]
All combustible elements make a sudden increase of air pressure in a small area, but they explode differently. C-4 only makes an air explosion, but nitro and gunpowder make fire as well. All explosives other than gas create shock waves that go through block, while gas only creates shock through the fire that burns through block.