the gameplay for this game is pretty boring. you use cards to complete tasks (which is basically the demon brothers in chibi form dancing. they are competing against the npcs to see who can fill the gauge the quickest. if you don't get past a certain point within a certain amount of seconds you fail.)
you get the cards from the gacha (its called nightmare in this game though) the rate is bad. the game doesn't give you the exact rate at which you can pull the cards but doing a bit of math it seems that UR is the highest and it's at about 1%. didn't look at the other one's because that's bad enough.
the game has a 10roll at the tutorial area but this is a fixed set of people you get. you get enough to do a 10roll after the tutorial. also rerolling is impossible unless you use an emulator and make multiple instances/drives.
the story is the most interesting thing so far but it is a "you're a human at a demon academy" story. the game has the voices in Japanese but you can play the game in English.
EDIT 1: something that bothers me greatly about this game is how touchy feely these guys are. they are supposed to be brothers. that shit is fucking creepy.