Thanks for the feedback! Under the hood Authmoji displays unicode, so it depends on the OS you're using. It should not be a problem if you enter the emoji sequence from the same phone you receive the SMS. We've also selected a subset of emojis that are very closely matched across OS. If you see any major discrepancies, please let us know!
Authmoji adds a fun spin on two factor auth and one time passwords by using emojis instead of numbers. We just launched, so let us know what you think!