Psychonauts Vault Viewer is a free app available for iOS 10 and lower (iPhone and iPad) that displays all of the Memory Vaults from Psychonauts along with additional commentary. Due to the app not being updated from 32 bit to 64 bit and Apple removing the ability to launch 32-bit apps in iOS 11, the app does not work on iOS 11 or later.
Psychonauts Vault Viewer was created by Double Fine Productions and released on September 30, 2011. Per the developer's description, it was created to celebrate the release of Psychonauts for the OS X (now called macOS) operating system.
The main screen provides a list of vaults that can be selected. Once a vault is selected, the user can either view it manually or the developer commentary can be enabled which automatically flips through the slides.
Due to the recent iOS 11 Update, the app is declared obsolete, and Double Fine released a video archive version online. The app still continues to be available on the App Store anyway, only to all iOS devices running on iOS 10 or lower. As of October 2017, there's no plans if an Android version of the Vault Viewer will be released.