Two new modes were announced, Live2D Mode and Rehearsal Mode. (Though, I don't think Live2D is an actual mode, just new options.)

Live2D Mode allows you to play with advanced visuals, such as new camera angles, enhanced lightings and, of course, Live2D cut-ins!

Rehearsal Mode lets you play a song for free and will continue even if you hit 0 life. A demo function will also play the song for you, letting you see how the beatmap is meant to be played!