Since you cannot download the game officially, you must sideload it using an (for Android). Note: iOS users are generally out of luck unless they previously "purchased" the game when it was live, in which case it may remain in their "Purchased" history on the App Store.
Reliable third-party sites maintain archives of older APK files for Android users: Temple Run Oz Game Old Version Download
When downloading an old version of Temple Run: Oz, keep in mind: Since you cannot download the game officially, you