Danmaku/Bullet-Hell NPC ships/weapons OXP

[BuggyBY]

OK, so as a great fan of bullet-hell shmups like Touhou Project (alas, definitely more of a spectator sport for me), I was wondering how feasible it would be to make a 3D version of countless, mostly slow-moving, bullets forming patterns to weave through. I had envisioned something like in this YouTube video (starting around 1:36), and there are also some Team Fortress 2 mods that go for a similar (though less impressive) effect.
With a freely-moving first-person protagonist (unless using some external views, potentially custom-defined), the 2D patterns are of course tricky to achieve, but would it be possible at all? I had envisioned it as a minigame sort of like the recently-released Asteroids3D OXP, as it's rather unlikely to be something I'd like to come across in my normal trading runs ... perhaps it could be an additional duelling choice at Royal Hunting Lodges in Feudal systems, though.

[Commander McLane]

I was wondering how feasible it would be to make a 3D version of countless, mostly slow-moving, bullets forming patterns to weave through

• bullets forming patterns: easy
• slow-moving: easy
  and one addition:
• hitting one of them damages/kills you: easy
  but:
• countless: tricky, because there is a maximum number of entities per system

But as I seem to have started a minigame career anyway , I may come up with a proof-of-concept OXP in one-and-a-half weeks or so (currently not at home).