iTunes lists the initial download size for XCOM: Enemy Unknown as 1.86 GB of required disk space. However, the true disk space requirement for this app is approximately 3.2 GB.
Please Note: When updates are released for XCOM: Enemy Unknown on iOS, the space needed by the app will exceed the 3.2 GB requirement. For the latest update, players will need approximately 4.5 GB of free disk space to download and install it successfully. Once the update is finished, the disk space used by this app will return to the previous size (around 3.2 GB).