In FNF vs Impostor (D-Sides) mod you will fight alien creatures who love music very much. To win, you will need to reflect the attacks of enemies. If the enemy touches you, you will lose your life.
FNF vs Impostor (D-Sides) mod has many different levels where you have to fight and each level will have different enemies. With each level you will meet new opponents, but it will be easier to fight with them, because they are weaker. Each character has their own special skills and abilities. The game consists of several levels, on each of them you can choose one opponent. On your way there will be various obstacles, and you will have to overcome them.