Vampire Survivors hit 1.0 release this week, and it brought with it a huge number of improvements and additions to the game, including a new (and apparently final) boss fight. It takes some work to reach this boss beyond simply surviving long enough, but it's the only way to see the Final Fireworks. Here's what you'll need to do to see the Final Fireworks for yourself.
How to Unlock the Greatest Jubilee in Vampire Survivors
Before you can even think about seeing the Final Fireworks, you'll need to have unlocked every relic in the game, and then unlock both Gracia's Mirror and the Seventh Trumpet. Once you've unlocked both, you'll need to enter the Eudaimonia Machine, where you'll find The Director waiting to speak to you. Hit OK through the dialogue and let battle be joined.
During the fight you'll have to fight the objects floating around The Director. The fight lasts five phases in total, with each more difficult than the previous. When The Director finally goes down, you'll see the Final Fireworks and unlock the Greatest Jubilee.