Super Mario Halloween (fan-made) is a spooky version of the classic Super Mario platformer. This one keeps the core of the original Super Mario games but with a darker theme and new levels in the Haunted Valley. You have to get through these levels, avoid obstacles and enemies.
You can kill enemies by jumping on their head, but be careful. If you touch them anywhere else you will lose health. Some enemies are invincible to this attack.
Note: You can also damage bosses this way, but they will also hurt you if you touch them anywhere else.