Toby Fox's Undertale subverted every RPG convention with gleeful precision. The combat system let you spare every enemy through unique bullet-hell mini-games. Killing monsters had permanent consequences that the game remembered across playthroughs. Characters broke the fourth wall, addressed the player directly, and called out save-scumming. The writing was hilarious, the soundtrack was phenomenal, and the genocide route was genuinely harrowing. Undertale made you question the basic assumptions of every RPG you had ever played: why do we kill things for experience points? What if the monsters had feelings?