It's not a Metroidvania, but you do keep all the stuff you find throughout the entire game, and you can go back to previous chapters whenever you like. Consider this more of a game with MANY endings, a lot of them very meta and relating to the fact that this is a game. It's kinda like The Stanley Parable but with gameplay beyond just exploring the world.

I like the gameplay; it's pretty satisfying. While the tone of the game is serious the endings get pretty silly and I like that. It's up to you whether this sounds appealing at all, of course.