Doesnt work with iPhone 4S?

I really want to play this game, but perhaps because of the formatting for an iPhone 5 sized screen, the check combination button is not showing in the bottom right corner of my iPhone 4S, so I cannot progress beyond my first guess or even see if it is correct. Please fix this and I will be happy to come back and give this a 5 star rating!

SpikeyvBill about Mastermind – Classic, v1.0