While the gameplay itself was superb, I find my love for the OST to outweigh it, its basically a must play if you like bullet hells/Carpenter Brut-esque music.
Simple. Very polished gameplay that while easy to pick up, it gets harder and harder with easily the highest mechanical skill ceiling in competitive games.
Competitively easily the worst fighting game. Conversely, the best story mode in a fighting game and a stepping stone for crossover experiences in gaming.