Why does the game run like poo on my iPad?

So a little background info. I have an iPad mini 2, 16gb, wifi, jailbroken. (I am planning on removing the jailbreak very soon.) It can run LLSIF and other games fine, but when it comes to this game, it either runs like crap, or just doesn't. This is a little disheartening since I'm not as good at rhythm games with my thumbs as with my indexes. :(

The game lags so bad it's unplayable, doesn't even make sound effects, such as the sound effects from tapping the rhythm icons... Switching 2D/3D doesn't help much. I should mention I have only a basic understand of Japanese and can't read most of what the settings say; I only know from testing.

Does anybody have any advice? I really want to play on my iPad ;____;

EDIT: Whoops. Forgot to mention one thing. I have an iPhone 6 as well and the game runs just fine on it. Hence the thumbs mention.