This is co-op pong, improved substantially with a "Magical Girl" story around it. It is designed to be split screen co-op, each player controlling one character, while a star bounces between them (the star "homes" at the characters, so no fear of actually "missing" it). Such star is the "projectile" you use to defeat your enemies, so correct alignment is key... which would be trivial if you did not have to dodge enemies and bullets (sometimes MANY bullets) as you go along.
Since I do not have friends, I played this single-player. It is clearly *NOT* designed to be played this way, but anyway it was possible to finish it (controlling each character with 1 stick of a dual-controller) and I would say it was enjoyable anyway. Just use your diagonals, prepare to die a lot, and save your super powers for the nearly impossible sections of the boss fights.
(I lie -- I do have friends, but they are too grumpy to play a game with Magical Girls and such a merry-go-round mood. If you growl when someone yells "Star Power!", this might not be the game for you.)
Anyway, I had fun: 72/100.