Some pledge tiers in the Kickstarter campaign included the ability to design NPCs, bosses, dungeons, and even a whole village. Backer-designed NPCs are Tiso, Cloth, Eternal Emilitia, Tuk, Grey Mourner, and most Ghosts, while the bosses are all Warrior Dreams, God Tamer, and other two bosses (one of which, Steel Assassin Sharpe, is slated to appear in the upcoming game Silksong, the other is currently unknown).
Backers voicing characters
In addition to the ability to design NPCs for the game, backers were also given the opportunity to provide voices for their characters:
The characters in Hollow Knight will speak in little snippets of an insecty, gibberish language that accompanies text boxes. Some examples can be found here.
Videos and trailers
Gods and Nightmares
Character Promotional Art
Stretch Goal Quests
One of the stretch goals at $44,000 was the addition of four new quests to the game:
|A Nailsmith's Obsession|
When his job is done; when the perfect blade is forged; what meaning remains for the Nailsmith? Is there something more the Hollow Knight can provide?
|The Lantern on the Black Shore|
Travel beyond the City of Tears to re-ignite an ancient flame. (includes an additional boss encounter)
Against fierce resistance, ascend through the city of a proud and ancient race and uncover the sad truth at its heart. (includes an additional boss encounter)
|Secret of the Stagways |
Travel to the end of the line and learn more of the stags, their history and their fate.
Artwork featuring all stretch goals presented during the Kickstarter campaign.
(The Colosseum of Fools, while displayed as not funded in the artwork, was met by donations on a later date shortly after the campaign had closed)
Early Concept Art
A series of art pieces drawn by Ari Gibson, known as "Hungry Bug", they were made after the game Hungry Knight and served as the basis for the creation of the world of Hallownest.
Menu Themes are used to customize the main menu of Hollow Knight. In addition to their main appearance changes, each one comes with its own unique background sound effect.
The Classic theme is close to the original one that came with the release of the game (slightly lighter than the original theme).
While the Hidden Dreams and The Grimm Troupe themes were added for their respective updates, the option to customize and switch between the different themes wasn't implemented until the Lifeblood Update.
The Lifeblood Update also introduced the Lifeblood, Infected, Void and Steel Soul themes; all but Lifeblood had specific unlock requirements that needed to be met in-game. In addition, the Void and Steel Soul themes had a colour desaturating effect that applies to the saves menu.
The Godmaster theme came with its respective expansion along with The Eternal Ordeal theme; the latter of which also required a specific unlock condition. The Eternal Ordeal theme also featured a cover of Zote singing the main menu track that replaces the original music.
Lastly, Voidheart Edition also introduced its own custom theme.