Picture, if you will, this scene from a top-down perspective.
You've just bashed your way through three bosses who share a single life bar, and you only have a couple of lives and smart bombs left (one hit kills, by the way). You have to maneuver through a whole lot of enemy projectiles, just from the standard enemies, and if you take too long to kill them then it gets even more annoying. Then, just when you think you're finally getting a breather...Mid-boss!
She rambles on for a bit before throwing a completely stupid number of projectiles at you, but it's easy enough if you know the pattern. Then, suddenly, the background goes dark blue, and some text appears in the corner along with a portrait of who you're fighting. Everything goes grayscale as the game enters slow-motion, and suddenly BAM! she's on the other side of the screen and a few rings of bullets appear in her wake. It doesn't look like much compared to something like Queen Larsa...but trust me, you'll have to make use of her bullet-time in order to survive. You'll probably lose a few lives here unless you really know what you're doing.
Another short section of "normal" enemies, then the mid-boss you just defeated appears again and rambles on, with your character talking as well this time. Then, the music stops and another track kicks in, as she starts attacking again with an upgraded version of her first mid-boss pattern. This isn't so hard to dodge...and then the background goes blue again. Oh, crap. Some ball of light you never noticed before starts firing out these blue bubbles, which explode like grenades as the boss uses her bullet-time slash again...and again...and again. This is where you will die. I'm not kidding.
And if you survive that, you've still got four more attacks to deal with, on very limited resources. And there's still one last stage (and boss) to deal with. And you only get a few continues, which you're not even meant to use.
~~~~~~
What I just described is my usual experience with Perfect Cherry Blossom, stage 5 on normal. While the boss (my avatar, Youmu) is easily the hardest part, her mid-boss appearance and the mooks will drain you of your smart bombs and lives. And while it's true you can't continue if you want the best ending, to make any sort of progress you really have to, at least the first few times. Since continuing doesn't kick you back to the start of the stage, it's a good way to practice her later attacks and the next boss. There's also a 'practice stage' mode, so if you beat this stage (any amount of continues) you can play it again and again until you get this fight down-pat.
Still, since I think I've had more deaths against this boss than any other I've faced, I feel like I have to put this down as my most difficult boss. And that's probably only because I don't have any experience with bosses like Spiritual Larsa or Yukari.
~~~~~~
Edit: To show you guys what I mean, here's a video of someone making that stage their ***** on the highest difficulty: http://www.youtube.com/watch?v=NJ6PhaebfHU That's not me. I only do Normal (level 2 out of 4.)
