If the player defeats the final boss of the game, called 'The Hollow Knight', they are given access to a mode called 'Steel Soul'. It enables the player to face more challenging versions of a few bosses, and to break what is sealing the path to the final boss. Later in the game, players acquire a 'dream nail', a special blade that can 'cut through the veil between dreams and waking'. Defeating some bosses grants the player new abilities. Many areas feature more challenging enemies and bosses which the player may need to defeat in order to progress further.

Initially the player can only use Soul to 'Focus' and regenerate masks, but as the game progresses players unlock several offensive spells, which consume Soul. The game continues from the last visited bench they sat on which are scattered throughout the game world and act as save points. Players need to defeat the Shade to recover the lost currency and to carry the normal amount of Soul. The player loses all Geo and can hold a reduced amount of Soul. If all masks are lost, the knight dies and a Shade appears where they died. By striking enemies, the knight gains Soul, which is stored in the Soul Vessel. When the knight takes damage from an enemy or from the environment, a mask is reduced. 'Mask shards' can be collected throughout the game to increase the player's maximum health. The knight starts with a limited number of masks, which represent the hit points of the character. Defeated enemies drop currency called Geo. The player can learn spells, allowing for long-range attacks. Melee combat involves using the nail to strike enemies from a short distance. In most areas of the game, players encounter hostile bugs and other creatures. The knight wields a nail, which is a type of sword, used both in combat and environmental interaction. The player controls an insect-like, silent, and nameless knight while exploring the underground world. Hollow Knight is a 2D Metroidvania action-adventure game, that takes place in Hallownest, a fictional ancient kingdom. Gameplay screenshot in which the player fights a large boss enemy, the False Knight. A sequel, Hollow Knight: Silksong, is in development. Hollow Knight was well received by critics and has sold over 3 million copies as of December 2020. The player is the Knight, a nameless warrior uncertain of their own identity or origin, who wanders and explores the ruined kingdom of Hallownest to uncover its mysteries, encountering various friendly or hostile bugs, fighting bosses, and unlocking new powers and abilities to progress. Development was partially funded through a Kickstarter crowdfunding campaign, raising over A$57,000 by the end of 2014.

It was released on Microsoft Windows, macOS, and Linux in 2017, and on the Nintendo Switch, PlayStation 4, and Xbox One in 2018. Hollow Knight is a 2017 Metroidvania action-adventure game developed and published by Team Cherry.

Hollow knight charm notches locations