Exporting to iOS device breaks game and causes errors

I have been struggling getting my exported Unity game to correctly function on my iOS device. I have experimented with the player settings for a couple of days now and cannot get my game to properly work. It's a little be tricky to explain, but when I play my game on a device, crucial aspects of the gameplay just don't function. This may be down to a couple of integer length warnings I've been getting once I compile my code in XCode, but after doing a little research apparently this isn't the issue. Hopefully somebody with experience on this topic can help, because I am extremely frustrated.