I used this youtube video to help define my target audience more.

My target audience:

Single-player Metroidvania gamers from 15 to 30 years old, with perseverance to fail and try again and learn difficult gameplay. They should have intrinsic motivation to explore independently and be interested in discovering narrative without it being handed to them.

Where can I find this audience for testing?

In the communities and fandoms of similar games, like the Ori games or Hollow Knight. I can contact them through social media, lie Steam, Tumblr, Discord, Instagram and Twitter.

1. Genre of my game

Game dynamics/ mechanics: Metroidvania, 2D adventure sidescroller platformer.
Exploration is rewarded with more content and gameplay ease. Hard gameplay where persistence and trial and error is required.
Story / game feel: Serious and in depth, with emotional meaning. Non-lineair narrative where intrinsic motivation to exploration is required to see most of the game.
Art: Magical, cute characters and an intense atmosphere and a serious story. Bright colours and a world that makes you feel small.

2. Similar games

Game Mechanics: Hollow Knight (Metroidvania) , Ori and the Will of the Wisps, (Metroidvania), Hyper Light Drifter (Metroidvania) , Night in the Woods (Narrative and dialog with choices), Life is Strange (Different endings, choices matter),
Story: Hollow Knight, Ori and the Will of the Wisps, Hyper Light Drifter, Gris,
Art: Hollow Knight, Ori and the Blind Forest, Ori and the Will of the Wisps, Journey, Celeste, Dead Cells

3. Sister genres

Game Mechanics: -
Story: Annihilation (film), Sleepless Domain (webcomic), Princess Mononoke,
Art: Steven Universe, Star vs. The Forces of Evil, Kipo and the age of Wonderbeasts, Coraline (film), Spiderman:Into the Spider-verse