The Lasting Influence of Castlevania: Aria of Sorrow on Metroidvanias.
Castlevania: Aria of Sorrow, which celebrates its 20th anniversary, introduced the Tactical Soul system, a mechanic that has inspired many of the metroidvanias that have emerged over the years. The system allows protagonist Soma Cruz to absorb an enemy's "soul" after slaying them, giving him an ability themed around the enemy's powers. The Tactical Soul system and its variants became a signature aspect of 2D Castlevania games following in the wake of Aria of Sorrow, and it has influenced other games in the genre like Ender Lilies: Quietus of the Knights and Record of Lodoss War: Deedlit in Wonder Labyrinth.