In Nightmare is a horror adventure game taking place inside a child's dreamworld. The child, traumatised by their broken family life, retreats to their dreams but is haunted by countless nightmares. They must navigate this nightmarish world, avoiding monsters and completing puzzles to finally find hope and wake up.
While most of this world is out to get him, the boy has help in the form of his dream spirit. This ghostly being can be used draw away enemies or reveal new pathways as you progress through each level. Enemies cannot be fought directly, so you must hide or temporarily incapacitate them and then make your escape.