ipod nano

so, i've got a ipod nano, and a friend at school shows me a game called crystal defenders, it may sound stupid, and im not into that kind of stuff, but i get home, and type it into itunes, and it comes under apps for the iphone? so how did he get it onto his nano? any help much aprechiated! i found a list from apple on games that are aparently for the nano, but they all come up under iphone too, seriously confused now

 

He's a magician.