Both Hollow Knight and Radiance do not contribute to game completion percentage, but you'll have to actually get to the end credits scene to receive the achievement.Dream Bosses (Lost Kin, Soul Tyrant and Failed Champion, etc.) do not contribute to game completion percentage, but are essential for Seer Ascension (1%).However, Vengefly King does reward 65 Geo and is fairly easy to kill, the reward Geo would be quite crucial in the early game. Saving Zote does not contribute to game completion percentage, the same goes for Vengefly King.(Talk to the NPC outside Distant Village Stag Station then talk to him again at the edge of Howling Cliffs where you summoned the Troupe in the first place.)
