The app is super buggy and runs like crap. Mercifully, the gatcha doesn't give you characters. You get those either way. The gatcha is for weapons and limit breaks. Unfortunately if you want to progress you'll need both of those things. The whole concept of slowly advancing the story of every game in the series, alternating between them all is cool and fun, but the devs decided long ago that none of those stories are every allowed to end.