A while back someone posted a (now-deleted) comment on the Fediverse about how they were able to construct a single unicode glyph of arbitrary length, e.g. a single character that could require 2MB of data to store.
The salmon code appears to be doing something similar - if you look at the source code in a hex editor, you'll see that the four spaces before "is very yummy" are actually a huge stream of F3,A0,81,93 and so on, where '93' is a varying number that may contain the actual payload (a recipe for cooking salmon). I don't know enough about unicode to tell precisely how it's doing that, but essentially it's some strange unicode trick.
However, I do not understand the significance of the 'grill' defines, since the code doesn't appear to be calling it in a way I'm familiar with, but it is also doing some unicode shenanigans with that too, and the code won't build if the 'grill' defines are commented out.
That was my first reaction, but the post actually says "Sequels and remakes". So given that there was a previous Dune film in 1984,it still fits in the list.
However, you could easily pick up a 2 inch deck, for example a 24 track tascam from eBay for a few grand and play it back on that. The one inch tape would cover 12 tape heads and you would for certain be able to make a copy. Not saying it would be the best copy you could make, which obviously would be from playback on the original source equipment, but the idea that the tape could not be played back and the information is lost is false.
That can work for audio - Frank Zappa did this to archive 1" 12-track tapes - but in this case, it's probably a C-Format helical scan videotape. You would need an Ampex VPR or Sony BVH machine to play it back.
There were 3 different standards for 1" helical scan video tapes, Type A, B, and C. I think IVC also had their own format. The reel doesn't say which the tape is.
For 1982 I would assume C-Format, though you never can tell.
Slowly and surely the unix crept up on the Nintendo user ...