SHIKIGAMI NO SHIRO 3

This game is old, but there is seemingly no information anywhere about the 3 Extreme achievements.
So throwing up info that I found or used myself.

For all 3 extreme achievements you need to 1cc the game - so complete all stages without using a continue.

Make sure to unlock extra options (complete the game with any character), then change them to -

Bullet Size : 50%

Game Speed : 50%

TBS : 200%+ (this allows you to kill enemies further away and thus keeping your score / combo higher so you frequently gain extra lives and bombs if not already maxed).

In the standard options choose 'very easy' and 'director's cut' - the latter is apparently the console version which removes un-dodgeable areas in the original.

I chose - Kohtarou Kuga
His secondary attack (Shiki?) when held down, locks onto enemies and you can just focus on dodging, note, some bosses it is more beneficial to use standard shot as more powerful (especially if you stay still and the shot changes red).

Achievement unlocks on the screen when you input your initials.

The ratio is low, even with the extra options I would not consider it 'easy', but very do-able.