Does anyone know how many times the NES game "Gradius" ramps up in difficulty?

[Peter1986]

I guess they might ramp up indefinitely, at least until the game cannot handle the intensity anymore.

Anyway, I made it to stage 6 in Gradius a while ago (the one with all the flying star enemies or whatever, and all the blue crap everywhere) on the second round, and that stage gets pretty ridiculous at that point.
Basically, if you die there then you might as well reset the game, since the enemies will be way too fast and chase after you all over the stage and surround you, and you won't be able to fly away or defend yourself properly.