Spoilers for Hollow KnightHollow Knight is an outstanding game. I don’t really need to state that, as awareness of the game's brilliance is everywhere.What I really want to focus on is this one powerup:(Artist : MadMonsterMutt The Dream Nail.This item dramatically changes, altering its scope, mechanics and narrative. It is an incredible achievement and deserves focus.The Dream Nail is an ethereal weapon, one that acts like no other. It has wide-ranging applications.The Dream Nail is Team Cherry’s clever way to include immense changes to tone and experience, without affecting the mood and consistency of the main journey. It grants access to dream states, surreal places where reality twists into insane platforming gauntlets, sneaky collection challenges, and overpowered boss marathons. It allows the designers to go crazy with their content and push their game into intensity, while also maintaining the integrity of their careful, quiet narrative.In other Metroidvanias, these heightened experiences in lunacy would normally be reserved for challenging ROM hacks. With the Dream Nail equipped, Team Cherry offer the player the chance to truly challenge themselves to a new level, and perfect their mastery of the intricate mechanics.When used on NPCs, the Dream Nail offers the player a range of manipulations:-On some NPCs, the Dream Nail acts as a lie detector of sorts, juxtaposing what a character is saying with their inner thoughts.-On bosses, the Dream Nail offers access to their mind, granting insight into their madness. This requires considerable care on behalf of the player, for using the Dream Nail on an enemy takes a few moments and requires careful timing, leaving the player vulnerable to interruption and damage.-On defeated bosses, the Dream Nail offers the opportunity to enter the corrupted souls of the world’s villains, and through arduous spiritual combat, relieve the beasts from their mental torment. It allows the player to volunteer themselves for immense battles, with the reward of – however briefly – meeting the spirit of the person that the boss had been before their corruption. Where physical combat relieves these monsters of their lives, this mental combat relieves them of their inner pain.-On enemies – the Dream Nail grants brief access to their stream of consciousness, allowing glimpses of their instincts and drives. There is a powerful moment when the Dream Nail is used on one of the game’s early monsters, a fly creature, and the player learns that the monster is living a life of perpetual unending terror, and the player is frightening it. Other insights include the desire to reproduce, to spread, to nest, and to consume. Through the Dream Nail, the enemies become entities, and the world becomes more of an ecosystem.-There is one deep, dark place in the game, where the player finds a reflective surface. When the Dream Nail is used on our character’s reflection, it grants insight into the mind and motivations of the most mysterious entity in the world – our playable character. It’s a remarkable mechanism for exploring backstory.The Dream Nail adds a layer of moral ambiguity to the world. There are NPC ghosts scattered across the land. The player is informed that by using the Dream Nail on these ghosts, the player can become stronger.The explanation of this is hugely problematic. The ghosts are hugely ambiguous. Their fate upon being struck with the Dream Nail, is left unanswered.Are the ghosts self-aware, or echoes of life trapped in purgatory? Does the Dream Nail free them, or consume them? What is the right thing to do?There is a moment, when the ghost of a divine singer voices a beautiful aria. When the Dream Nail is used, she is forever silenced, and the player can never again hear her song. There are umpteen results across the internet of players asking how to undo their actions.The Dream Nail is the mechanism from which the player can access the entirely optional, higher story of. By mastering the powerup, and using it at precise moments – upon which the player themselves must identify through visual and narrative clues – we are granted the opportunity to understand the true power struggle taking place. The player can end the game without mastering the Dream Nail – and bring a form of resolution to the crisis. But with it, they are granted access to the celestial war overshadows all that has taken place.The Dream Nail is the most exciting Metroidvania powerup in recent times, and in my view - one of the most versitile powerups ever conceived in the medium. It heightens the experience immeasurably. Future Metroidvanias are going to struggle to match just how cleverly Team Cherry conceived and implemented this powerup.