I can't play my game

I bought Titanfall from the xbox marketplace on my Xbox 360 but it won't allow me to play it because apparently I need an Xbox 360 hard drive in order to play it. I use a USB cable to store my memory instead of the hard drive so I can have more room to play my games. Before I downloaded it, I looked under where it said Capabilities and it didn't say anything about requiring a hard drive in order to play. Does anyone know if there is ANY possible way I can be refunded or I can play the game?? Please me out somene. Thanks.