Music, aesthetics, story, lore, personality, style, even gameplay...
I love Galbrena's style and themes (With Glory I Shall Fall, and With Glory I Shall Fall), female Rover's style, the Black Shore's styles and aesthetics, the setting and lore overall, like some kind of "post-apocaliptic high-tech fantasy", some random songs (With Glory I Shall Fall, and Saving Light), and the gameplay in combat, specially parries, perfect dodges and boss stunt, gives "epic anime combat" vibes.