Beyond Zork

1. In versions 47 through 51, there is no response to UNDO when the skeleton is choking you.
2. In all versions, if you're sitting on the saddle on the rug then you can GET RUG, or you can pick up the saddle using EMPTY RUG or GET SADDLE FROM RUG. Similarly, while sitting on the pterodactyl you can pick up the saddle using GET SADDLE FROM PTERODACTYL. After any of these, the next command locks up the program.
3. In all versions, giving the Ur-grue an electric shock causes a crash. Frotz exits with the message, "Fatal error: No such property". --Dan Weber
4. The DIP ME IN POOL bug is much more than that. In all versions, you can perform several actions with objects that you really shouldn't be able to. You can DIP things IN POOL or in a body of water such as BROOK or SEA, HANG things ON TREE in a location that has an oak tree (Twilight, Mountain Pasture, or Hilltop), or PUT things UNDER something such as PEW or RUG, or BEHIND something such as TREE or BOULDER. The unusual objects you can use include ME, MY HAND or FOOT, a direction, or the parts of the hurdy-gurdy: EYE, EAR, DIAL, NOSE, HAND, CRANK, MOUTH, or CLOCK. If you DIP something IN a body of water, then it disappears; the other actions leave the object at that location. The only one of these objects that shows up afterward is "yourself", but you can interact with the others at that location. After you do this you can still refer to CRANK or DIAL in locations other than where you left them; in this case these are considered synonyms for the hurdy-gurdy and work correctly. You can also continue to interact with the "direction" object after leaving it in one of these places. DROP WEST (or other direction) gives different messages depending on where you left it.
5. In all versions, when the bearskin rug is present but not in your inventory, you can PUSH almost anything UNDER RUG. In most cases the object reappears when you pick up the rug. You can do it to stop attacking monsters. If you do it to Cardinal Toolbox you can take the reliquary. You can put the rug in the sea chest, and shove stuff under the rug, and then get the rug. That stuff will be in the chest. This appears to be one of the most powerfully exploitable bugs in the game. A large amount of detailed examples can be found at this blog entry by Dan Weber. The variations are almost endless. --Dan Weber
6. In all versions, you can get the effects of the amulet to last much longer than intended. If the amulet is not in your inventory, speak its magic word and then WEAR AMULET. You don't pick up the amulet, but you get the strength bonus, which slowly ticks down to your normal strength. --Dan Weber
7. In all versions, EAT WEED behaves buggily at Edge of Storms or Glare. You can use this to heal yourself without limit. Normally, you can only get 2 spenseweeds, one from each of these locations. However, if you haven't taken one yet, you can EAT WEED at one of these places, followed by GET WEED there. In fact, if you haven't yet used GET WEED at Edge of Storms, you can EAT WEED at Glare over and over again. This can make it much easier to defeat the ghoul, after which you can still GET WEED for later use.
8. In all versions, when you PUT a worn or wielded object UNDER or BEHIND something, such as BEHIND TREE or UNDER RUG, its state doesn't change. You can GET it, and it will still be worn or wielded. Since WIELD only sets aside an already-wielded object if it's in your inventory, you can use this to WIELD multiple objects. You could WIELD your entire inventory! You can't use this to do extra damage by wielding two weapons, however. Apparently, ATTACK MONSTER only attacks with the first wielded object. On the other hand, you can WEAR multiple suits of armor and get the total of their armor class bonuses. You don't even have to have the armor in your inventory to benefit from it.
9. In all versions, it's possible to physically attack the monkey grinder, using the command THRUST. He never seems to regenerate hit points, but he must have a lot; it takes a long time to defeat him. He can also be damaged by electric shocks. --Dan Weber
10. In all versions, if you POUR an open, non-empty container, you get a list in which each item inside it is followed by, "The [object] is too big to fit in the ground.", with the exception of the following objects: the gold doubloon, ring of Shielding, four-leaf clover, vague outline, tear-shaped jewel, or small diamond. When you get to one of these on the list it says, "Done.", and the object is apparently lost forever.
11. In all versions, opening the chest doesn't stop time-based events. For example, if you open the chest during the tornado in the farmhouse, or the gathering in Froon, then you continue to get messages about what's happening there, even though you're in the Plane of Transfinite Splendor. If you open the chest during the gondola ride, then the gondola moves on without you, and when you come back you may be stuck in an inescapable jungle location between support towers. In this case the gondola doesn't ever come back.
12. In all versions, it's possible to get a lit lamp into the dark Underground passages. If the closed chest is on the ground there and you have the unlit lamp, simply open the chest, then light the lamp while on the Plane of Transfinite Splendor. When you are returned to the caves, the lamp doesn't get destroyed. --Dan Weber
13. In all versions, if you SIT ON SADDLE while you're in the stall, gondola, or pool, you're considered to be outside it. You can't get anything from it, but anything you drop lands in it. This is especially strange in the gondola, which goes on without you.
14. In all versions, the mother hungus won't attack you while you're standing on the rug or sitting on the saddle.
15. In all versions, after the farmhouse has landed in Froon, if you GO THROUGH WINDOW you fall to your death as if it were still flying.
16. In all versions, if you use magical means (Recall, Gating, the chest) to escape from the idol with the mother hungus on it, then she stays there instead of coming down after you. You can get back up, but she somehow blocks your way down.
17. In all versions, if you try to POUR or EMPTY the closed hurdy-gurdy you get, "There's nothing in the hurdy-gurdy.", whether or not there actually is.
18. In all versions, some things don't work consistently if containers are nested too deeply. For example, the Chalice doesn't ward off lightning if it's in the hurdy-gurdy in the pack. Similarly, you can PUT things IN or GET things FROM CHALICE when it's in the hurdy-gurdy in the display case.
19. In all versions, as Royal Garden, trying to PUT something besides the jar IN STATUE says, "The statue has no obvious openings.", even if the secret compartment is open.
20. In all versions, if you ZAP NYMPH WITH ROD Outside Guild Hall, then you get the same message as if the warning nymph were really there, although other commands--including POINT ROD AT NYMPH--say it isn't. This inconsistency exists whether the nymph is dead or alive, and even before it has appeared!
21. In all versions, you can't get on the rug in the stall, gondola, pool of radiance, under the arch, etc. You're told you have to remove the rug first.
22. In all versions, if you ZAP an untakeable inanimate object WITH LEVITATION you get, "Your strength wanes sharply as the rod of Levitation struggles for influenceover the [object]."
23. In all versions, when you're sitting on the saddle, STAND says, "You're already standing."
24. In all versions, if you ZAP BUTTERFLY WITH LEVITATION, you get a message about the butterfly rising off the ground and landing on it again, even though the butterfly is either "fluttering around your head" or on the rim of the Chalice.
25. In all versions, THROW something AT LAMP says, "The lantern is permanently sealed."
26. In all versions, at the Implementors' lunch, X TABLE says, "You see a food on the table."
27. In all versions, you can't PUT CHEST ON RUG, but you can DROP CHEST while standing on the rug. If you OPEN CHEST while it's on the rug, you get, "You'd have to put down the sea chest to do that."
28. In all versions, if you're on the ground at Idol, the response to DOWN is, ". You're not in the maw."
29. In all versions, if you're wearing the non-empty pack, your inventory says you're carrying the pack but wearing nothing unusual. If the pack is empty, you're told you're wearing it.
30. In all versions, if you DROP AMULET while you're wearing it and its magic is active, then you take it off, but it stays in your inventory, although you're specifically told you drop it.
31. In all versions, after destroying the dome, GET LAVA says, "The hardened lava cannot be moved.", even though it's hot and flowing. --Dan Weber
32. In all versions, at Shady Wall, despite the fact that you are "beneath the shadow of a towering wall of rock", EXAMINE SUN says, "The sun is as bright as ever."