Your app is pretty modular by nature. Meaning you can add any elements you want. I though there was some restrictions related to pitching each drums individually (and other things) due to instruments on it's own channel but you seem to confirm not. That's why I said it wasn't fully modular.
It wasn't a bad critic or anything. I'm really liking the app a lot and you guys have put in some serious though behind it.
Sorry if I don't explain myself clearly sometimes. English is not my native tongue.
I heard a native ipad version is coming! Looking forward to that cuz I have an iphone 5 and an ipad air 1.