It's got:
-Really interesting story and re-imagining of Greek Gods tied to the roguelike mechanics (dying over and over, randomly changing layout/items etc).
-Full voice acting, and this isn't baby's first voice acting playset oooh no, there are several thousand lines of dialogue, 3000 added in the latest update before the game left early access. There is no character I dislike or think is written poorly, and with 30 or so of them that's really great.
-Incredible art style oozing with charm and lovable character design.
-Music slaps
-Difficulties that scales from "I just wanna see the story" to "why is blood flowing out of my keyboard?"
-Tight, responsive controls that give you complete control over your character, Zagreus. Not once have I ever felt like it was anyone's fault but my own that I missed / got hit / died.
-6 different weapons, all with upgrades that alter their play-style, and ~100 boons from the Olympic Gods to further customize each run.
-You can romance the floating Gorgon head maid, Dusa. Also Thanatos(Death) because Zagreus is just that hot. That last sentence is a pun because Zagreus' feet are on fire.
-Cerberus is a very good boy. You can pet him.
-You can straight up have an assault rifle with under-barrel grenade launcher for all you Call of Duty dweebs.
-Delicious Pomegranates.
-Ghosts wearing construction helmets.