intro
this guide will cover basic lore and mechanics. leave if you do not want any spoilers.
Firstly, hollowknight is a 2d platformer metroidvania by team cherry. This game genre places a strong focus on exploring vast, non-linear worlds and often having features like inaccessible areas that you are meant to come back to later, usually with various upgrades.
lore
once upon a time in the kingdom of hallownest bugs lived under the rule of The Radiance, a higher being. Soon came along The Pale King, who established sentience among bugs, gave them an economy and contributed to great feats, causing the bugs to worship him and forget about The Radiance. She did not like this, and spread the Infection among the lands, which is reaching out to bugs in dreams and making them remember her. Remembering this would cause the bugs to the mindless state before The Pale King came along and fighting it would only worsen the effects. The Pale king formed a plan to deal with The Infection, which was to birth a being that would seal the radiance away. These were vessels, children born in the void of the abyss to be pure and without mind, so that the Infection could not affect them. Pale King created many vessels, but they all failed, as they were not completely void of mind. Finally, he created the Hollow Knight, a perfect vessel. The Hollow Knight was sealed away in the temple of the black egg. However, the Hollow Knight was not as perfect as The Pale King thought, as it had a small amount of mind because he loved his child. This caused The Infection to leak into hallownest corrupting the minds of many bugs.
mechanics
you can pogo jump with your nail on almost anything, which boosts you higher, damages bugs and have greater mobility. You can also strike with your nail in any direction, as long as yu hold the up/down key.