I've been playing through every adventure ever made in chronological order, so you can watch me do it so you don't have to

http://bluerenga.blog

just reached 1983 which has Planetfall

The "I can dig it" happens if you do DIG on any object other than I think the dirt. Just DIG alone is what tests digging in a room (except it only works in the starting room to find anything).

Do you have any good pictures of the tape? There's a Youtube video of someone playing it on hardware so you can see the tape inside of the machine, but no clear pictures of the real tape.

(Also, hello, I wrote the post! There's a part 2 where I finish the game, and I'll be doing the other Interact adventure game, Mysterious Mansion, in about a week.)