I haven’t played this game. I don’t know if I would want to, I’ve just been looking at the animation!
No outlines, often solid-color vector bodies with simple shapes that move like bending noodles. Contrasted with more paint-like, gradient- and pattern-heavy backgrounds. Vibrant special effects with lots of glows and bloom. All very cohesive, able to build a variety of atmospheres depending on the mood. Very neat.