Minor Note: Medusa Head spawner works off-screen

Except for one of the spawners created for CV3u, Medusa Head spawners in general will not deactivate when outside the screen. All other enemy spawners, including endless spawners like zombies and bats, will prevent creation code from running while off-screen.There is actually one Medusa Head spawner which deactivates itself, however. I don't know if the lack of a status check was an oversight or if the inclusion of a status check was an oversight. With that said, it's something to bear in mind when designing stages with Medusa Heads in CV3. As for why there are so many Medusa Head spawners, one spawns across all enemy registries; one spawns in the lowest registries (fyi, this checks spawner status) and one spawns in the highest registries; this avoids conflicts with certain enemies or terrain obstacles.