Black Mirror: Bandersnatch easter egg

At the end of Black Mirror: Bandersnatch there's sometimes a scene in which the main character plays a tape that says Bandersnatch demo. These are not modem noises, but an actual computer program for the Sinclair ZX Spectrum.

You can load that program using a Spectrum computer or an emulator. After you load it you'll get a clue that indicates what to do next.

If you don't want to follow the whole process here's the solution (very minor spoilers, use rot13 to decode):

• Nsgre lbh fpna gur de pbqr naq sbyybj gur yvax lbh'yy frr n jrofvgr jurer lbh'yy trg gur punapr gb qbjaybnq n GNC svyr jvgu bar bs gur tnzrf fubja va gur zbivr (Abumqlir). Lbh pna ybnq vg jvgu n Fcrpgehz rzhyngbe. Urer'f gur jrofvgr yvax sbe gur ynml: uggcf://ghpxrefbsg.arg/rnyvat20541/uvfgbel/

Files and links:

• Here's a recording of the audio in WAV format: bandersnatch.wav (821 KB)
• Here's the TAP file (for use with emulators) created from the audio data: bandersnatch.tap (1.8 KB).
  • You can load the program with any Spectrum emulator. Here's one that you can use directly on your browser: JSSpeccy. Simply press the Open file button (the second one from the right) and select the TAP file.
• If you don't have an emulator or you don't want to load the program yourself, here's a video that shows what happens if you load the program on a Spectrum: https://www.youtube.com/watch?v=UBJNXzfZ4pw.
• Here's another video with the full loading sequence: https://twitter.com/StuAA/status/1078655818357194752.

Questions, comments and corrections: bertogg on Twitter.