In Nightmare achievements

Use Bikti's sonar ability to locate 100 enemies.

Find the path hidden behind the mirror in Chapter 1

Use the Exorcism Lamp to repel Dark Nightmare when she is less than 1 meter away.

Find all of Ginger's Parts and activate the puppet show in the Dream Hall.

Destroy all the walls in the ice maze in Chapter 5.

Find all the Paper Cranes and let them soar again in the sky.

Gather all the collectibles from every chapter.

Unlock all accessories.

Find all the Lighthouse Fragments and let the lighthouse run again.

Place all the necesssary collectibles on their respective platforms at the end of Chapter 6.

Use Bikti's Detect ability to find 5 hidden footprints.

Defeat Chaotic Nightmare.