If we're talking about the original one here, I have (I actually ran it once, though I never did anything with the run), and I really don't like it much. From what I can tell, the level progress is measured by the number of spheres cleared, so there's no real way to speed things up other than to just spam shoot as fast as you can to clear everything as fast as possible. Without gap shots or combos that matter there's no reason to do anything risky. All in all it just feels like a super long auto-scroller. And I mean super-long...the game just drags on and on and on because the levels get so long near the end.
I feel pretty much the same way. The game just becomes a giant drag near the end due to the high number of spheres required. Only reason I am responding to this is because I just did a run of the game. (5:28:46) It was alright except for the game being a drag, and cobraic twilight (FUCK THAT LEVEL)