No there is something clearly wrong with the iPhone coding of this game, it runs horribly on every device I have tried including iPhone 4S, iPhone 6 Plus, iPhone 6S plus, iPhone 7 Plus, iPad Mini 2. I used to play the game on a Galaxy S4 active 3-4 years ago and it ran it perfectly.
These newer devices have several times the necessary power to run this acceptably yet they run as poorly as a 5 generation old device. I have a brand new iPhone 7 Plus with the ONLY thing on it as Madskills MX2 and it runs horribly choppy and laggy. Fresh from apple, only application installed it Madskills, same performance issues as device loaded with apps.