Here is the full list of all 13 NiGHTS Into Dreams achievements.
Clear Spring Valley (Christmas).
Clear all stages with a score of Rank A.
Clear Twin Seeds in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Clear Stick Canyon in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Clear Frozen Bell in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Clear Soft Museum in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Clear Mystic Forest in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Try to guide the lost car in the Mystic Forest to the garage.
Make a Nightopian and a Nightmaren have a hybrid offspring.
Clear Spring Valley in either BRAND NEW DREAMS or SEGA SATURN DREAMS.
Try to Paraloop all of Gillwing’s tail in one hit.
Show your supreme skill by achieving the highest Acrobat Time rating, "DREAMY".
Clear Splash Garden in either BRAND NEW DREAMS or SEGA SATURN DREAMS.