|Aunt Em in the barnyard|
"Look" provides a description of the item you select. Sometimes there are clues to what to do in the game are hidden therein.
"Talk" allows you to talk to a character, or, in the Nome King's palace, guess at which object is the Scarecrow. If you already know what you're doing, you're not going to use this much, but it is required in some parts to advance in the game.
"Search" is a catchall for "open" or "examine," allowing you to find more items by looking at items on the screen. Yes, this is needed quite a few times to advance in the game.
"Get" allows you to add whatever items you find to your inventory, which is accessed by "List," but more on that later.
"Leave" lets you move on to another location.
The problem with this submenu is that every emulator I've played the game in (I don't have a real C64) uses a different key to exit the submenu. (Which is also how to cancel selecting an item from the picture on the screen.) CCS64 uses "shift," and Frodo for Android (which I used to take these screencaps with) uses the emulated F2 key. On the Java emulator I set up on my Oz website, you have to use the Caps Lock key. Basically, experiment until you find the proper key. (Shifting between options uses the space bar, while confirming them is, of course, the Enter key.) A similar issue has prevented me from trying the Spectrum version, which has wholly different graphics.
EDIT: I have since tried both the Amstrad and Spectrum versions. Bafflingly, in these versions "Quit" in the inventory submenu actually lets you leave the submenu rather than quit the game. I managed to finish the Amstrad version, but had problems with the Spectrum version.
After recovering Tik-Tok, you have to go underground because the bridge to Mombi's palace is broken. Along the way, you face off against a nose on two legs (you use dust to make it go away), a flame-spurting carrot (somehow Billina destroys it) and a pit of lava. (You have to close the floor.)
An addition to Mombi's palace is that when you go to get Mombi's ruby key, you must drop your shoes either in the tower room or in that room before searching Mombi's bed.
On the Nome King's mountain, there's an optional quest to connect a tunnel leading to it to the one under Mombi's palace. (So perhaps it actually does have a connection to the movie.) Along the way, you run into a crab who can turn people to stone with the way it looks. (It simply blocks your path. It's defeated by showing it a mirror down the tunnel.)
The Nome King will not transform your friends, but says that if they fail all three attempts at freeing the Scarecrow, he'll send them to Mombi's palace. (The quest to connect the tunnels is to simplify returning to the Mountain.)
And, of course, those Ruby Slippers look stunning in those VIC-II graphics!
And of course, at the end, you set Ozma free. Not by using "Search" on the mirror, you have to add it to your inventory and "Use" it to free Ozma. To get the ending, you drop the Ruby Slippers and leave the Emerald City. And look at that ending screen!
Other sites have the Amstrad and Spectrum versions available for online play and download.
Here's some more screencaps.