Idle Nightmares is quite an interesting game because you have to fight your deepest fears to maintain your sanity. The unique combination of horror and progressive gameplay challenges you to manage resources, upgrade defenses, and face horrifying creatures. As you delve deeper into the nightmare world, you will encounter many monstrous enemies, each with their unique abilities. To defeat them, you need to collect sanity points, unlock powerful skills, and invest wisely in upgrades.