To play the game from your hard drive, you must extract both ISO files and place them in the correct directories.
: Use a tool like Xbox 360 ISO Extract to convert both Disc 1 and Disc 2 into folder (XEX) format. Install Disc 1 (Mandatory Content) : Alien: Isolation ISO & XEX DLC - Xbox 360 [Re...
Place the extracted Disc 2 files in your standard Games directory (e.g., Hdd1\Games\Alien Isolation\ ). To play the game from your hard drive,
Launch the game using the default.xex file found in the Disc 2 folder. Alien: Isolation ISO & XEX DLC - Xbox 360 [Re...