It's a rhythm game featuring Hatsune Miku!
The game has SEGA's attention to detail in making rhythm games with its storied history of Project Diva games. The mechanics are great, responsive and punchy (sparkly)!
The games introduces to us a cast of new characters with their own voice acting and personal storylines with their twist on things. The virtual singers from the titular, Hatsune Miku, and her team are all voice acted (which is a rarity considering the past Hatsune Miku games usually featured just a blurb by each character if any).
Throughout the 'live (perfomances)' your team will interject when their skill takes effect and that add even more interaction and hype to the already stellar song list bringing together Hatsune Miku and (vocaloid for that matter) classics and new blood!
This game already features songs that are non-piapro (i.e. beyond Crypton's singer team).
This game also features a virtual live where players can participate as audience members in performances by Hatsune Miku and her virtual singer team, as well as, performances by the other bands! It's an interactive live where you can emote along with the song and spend your crystals to add on effects during the concert. By the way, Miku is an ANGEL!
There's so much more to discover in the world and game of SEKAI. So stop reading and start playing! Hatsune Miku and SEKAI is calling!