There are two versions, Fire Cannon α and Fire Cannon β.
Fire Cannon β
This version of the Fire Cannon is the simple version and is found in Stage 3. They are generally fixed on walls, ceilings and floors and just throws flames in a timed way. They can be easily destroyed and doesn't pose major problems.
Fire Cannon α
This version is the most advanced, and is found in Stage 7. These ones will not only shoot flames in a continuous way but they also can't be destroyed and the only way to pass through their flames is by using the stage layout or certains enemies such as Rutas to the player's advantage.