The team is aware that BioShock Mobile is available to be purchased on iTunes, even if you do not own a compatible device for the app.
BioShock Mobile does not support the iPhone 4s and below. Likewise, the iPad 3 (AKA the “New iPad”) and older are not supported.
Please note: Your iOS device needs 1 GB of RAM in order to play BioShock Mobile.
If you are unsure of your device’s RAM, please check out this list of iOS device specs on Wikipedia.