This is a horror in which you must monitor and watch anamtronics which are active. Throughout the night they creep closer but you can't always keep your eyes on them because you'd lose power and potentially lose your life. The way to win is to survive 5 nights at the titular pizzeria.This game has many sequels and tons and tons of lore(thats part of what makes it so fun).
The lore is the best part of FNAF. Theories, canon lore, and icebergs gaLORE.
Mat Pat FNAF playlist(in order)
Most recent full FNAF timeline (2022 latest updated)