Enter Bullet Hell!

So I’m trying to start a shmups collection but i have no idea where to start. Do any of you guys know any good shmups with an extreme difficulty. I’m looking for some for pc, ps1, and ps2 but any console is fine.
Also feel free to add any of the shmups that gave you the most hardest time and wasted all of your quarters at the arcades. :eek:

Here is a list of what i know of any good ones so far.

-Touhou series
-Triggerheart Exelica
-Striker 1945
-Wartech (More like a vs/shump/virtual on type)
-Ikauraga
-Mushihimesama Futari (Or any game by Cave)

I think out of that list the hardest one was Mushihimesama Futari. I mean the final boss and even the LAST TRUE Boss is just a…. NIGHTMARE! That boss has to be on the TOP 10 of the most diffcult bosses.

Here it is to prove it :

MUDA~MUDA~MUDA~MUDA~MUDA