Keep a light on. You might get eaten by a grue. And by “might be,” it will happen after your warning if you make a move into deeper darkness or don’t light your lantern. The monster was borrowed from Jack Vance’s Dying Earth and used post-Zork in other novels and games.
There’s more than one way to skin a cat or get past a cyclops. While much of Zork’s puzzle solutions are linear, there are a few that aren’t. Even in today’s games, getting past an obstacle means fighting or finding the single solution/ key to continue progress. In Zork, the big one-eyed guy gets hungry (it might be you) and will also get thirsty (hope you didn’t drink the water yourself, or eat the lunch for that matter.) But he also really doesn’t like his older, more famous adversary or hearing his name. Hope you can spell it correctly. The game accepts two different versions of the name which the cyclops hates to hear.
How to make a map. When inside a text maze with identically-described rooms, the adventurer has little choice but to be lucky or smart. With Grues and an annoying thief amok, bet on smart. Dropping items, hopefully things that won’t be immediately needed, one per space, will result in a flowing chart style map of landmarks (e.g. from the Nasty Knife, you can go N, S, SW, or E) where movement in ten directions may be possible (points of compass plus up and down.) This left me over-prepared for other games and usually disappointed at how easy mazes became.
On a practical level, I learned to type playing these games. The intelligent parser allowed for full sentences, including prepositions. Previous games were restricted by commands like get item, use item, directions without a verb (although this does work in most Infocom Games including Zork), and other simple sentences. Of course in Zork, any word longer than seven letters can be typed out, but an adventurer who doesn’t need the extra letters can stop typing after the seventh and the parser won’t know the difference.
Plugh! Several early games recognized this command, all stemming from the original Adventure. What used to be a magic word of teleportation shows up in Zork and in other places. Try it out. Hilarity may ensue. At least it might strike you as mildly interesting. This may also lead you to try other commands seemingly unique to various games that got dropped into places like Zork. Easter eggs like these persist to this day, and the best are the obscure ones that only a few players actually find.