Few questions

[Maranatha]

To get the achievement H4><0rz can you get it while playing through on super hard?

Also can you unlock super hard by playing through on normal?

[Maranatha]

Was also wondering do you need to finish the level after getting the Yashichis to get the achievement or is just obtaining it enough?

[AmbiguousCrossup]

To answer the first two: Yes.
#3. Just collecting it is enough.

[Maranatha]

Thanks for the reply man!

[MM209]

Super hard will unlock even if you beat the game on easy