"Long ago, two races ruled over the Earth: HUMANS and MONSTERS. One day, war broke out between the two races. After a long battle, the humans were victorious. They sealed the monsters underground with a magic spell. Many years later... MT EBOTT 201X. Legends say that those who climb the mountain never return."Undertale is a Role-Playing Game by Toby Fox, released on September 15th, 2015. Its development was the result of a Kickstarter campaign that raised $51,124. The game and a demo are available at http://undertale.com/ and trailers are here and here.It tells the story of a young child who investigates a mountainside cavern and falls down a deep hole, awakening on a bed of flowers in a dark and mysterious place. Now the child must find a way back home, encountering all manner of creatures along the way.Undertale borrows heavily in atmosphere from EarthBound and MOTHER 3, and uses combat mechanics similar to Bullet Hell games, where you must dodge enemy projectiles and protect the heart-shaped avatar representing your SOUL. The game's story changes significantly depending on how you deal with the monsters you encounter: you can fight and kill them to earn LOVE (LV) and EXP, or figure out how to befriend and show them mercy.Compare and contrast other indie RPGs with a MOTHER flavor: Lisa, OFF, Ib, Anodyne, and Space Funeral; and Iji* . Contrast Citizens of Earth.Before reading the tropes section or other sections, please note that by its very nature, Undertale is very difficult to talk about at length without spoiling it. Read with care.