I've seen this before but have always wondered how they made the bytecode part of the game. Did they have an editor or just plot things out on paper and then test in the virtual machine?
Here's the official manual for SCUMM: http://wilmunder.com/Arics_World/Games_files/SCUMM%20Tutoria...
And the official tutorial: http://wilmunder.com/Arics_World/Games_files/SCUMM%20Tutoria...
There are several post-mortems about Maniac Mansion that go a bit into the creation of SCUMM: * https://www.youtube.com/watch?v=wNpjGvJwyL8 * http://www.gdcvault.com/play/1014732/Classic-Game-Postmortem...