The Hallway just updated to version 1.0.1 with PS Vita TV support.
Previous version was working only on PSTV's with whitelist patch, but now you can play the game without the patch.
It was a small missing feature but now it's added for the PSTV users.
You can download the vpk file from the Google Drive link below:
To install the vpk on your homebrew enabled PS Vita I recommend to use VitaShell. Also it is recommended to have the reF00D plugin installed.