Invincible Card Game: Aftermath why does this iteration vie for a spot in my top 20 of all time?

About Invincible: the Card Game – Aftermath, from BoardGameGeek:

Invincible: Aftermath is a cooperative deck building game where your deck is never shuffled. Your goal is to defeat the Boss before it destroys your team or the Homeworld you're defending. It is a standalone expansion but can be combine with Invincible: The Card Game. In each battle, you start with a character-specific deck of cards and a unique special ability, then it's up to you to build up your deck, charge your power, and choose your strategy wisely. Your enemy won't be taking it easy on you, unleashing hordes of minions to take you down, launching attacks to destroy the city around you, and forcing you to adapt to their unique special abilities. The game can be played as a single battle or in a campaign mode. As you progress in the campaign, you'll gain team attacks and combo abilities to strengthen your team. After each fight, the villains grow stronger, forcing players to adapt their strategies continually. In addition to new Bosses, Cities, Inventions, Combos, and Team Attacks for Expedition Mode, an all new mechanic is added - Bystanders! Players lose if their health goes to zero OR the Villain meets any specific win conditions as outlined on Villain cards. -description from the publisher