Elephant in the room first, the soundtrack. I LOVE you Mick Gordon. All of his Wolfenstein and DOOM 2016 stuff was already peak, and Eternal’s soundtrack just delivers that tenfold. I think the music is one of the key factors to why the gameplay feels so good. The new mechanics like the meathook and the dash add to the already super fluid combat from 2016, and just make it the most fun FPS I’ve experienced.
Also, as a huge doom fan, I love how accurate this game is to DOOM 2 from 1994. The designs literally just look like modeled and upscaled versions of the demons from the old games.