Infidel

1. If you're wearing the knapsack, you can PUT KNAPSACK IN almost anything visible, including many closed containers and nearly all non-containers. One fun thing to do is PUT KNAPSACK IN AIR. Now it's always accessible to you, so you don't have to carry everything in your inventory. LOOK IN AIR shows the knapsack and its contents, and you can GET things from the knapsack or PUT things IN it.
   This knapsack bug is why it's possible to put the knapsack and another container inside each other. If you have the knapsack, the cigarette pack, and other things in your inventory, then PUT KNAPSACK IN PACK followed by PUT ALL IN KNAPSACK crashes the game. Frotz exits with the message, "Fatal error: Stack overflow".
2. You can PUT BEAM IN CRATE to take the wooden beam without ever going below decks.
3. When carrying the navigation box, you can DROP BUTTON.
4. If the canteen is full of sand, then POUR SAND ON something says, "Poured. The sand is gone with the wind." Now EMPTY CANTEEN claims it's already empty, but the "quantity of sand" still shows in the canteen.
5. If you BURN BEAM while standing on it, then break the plaster, then the beam reappears in the niches, and you're safe.
6. If the rope is tied to the altar and you PUT ROPE ON ALTAR, but nothing else is there, then EXAMINE ALTAR gives no output.
7. You can POUR JAR when it's closed, emptying it of the oil.
8. If you SHAKE RING, the needle "spills out" of it, but it still pricks you if you put on the ring.
9. If you PUT ROPE IN a container at Chamber of Ra when it's tied to the altar, then you can't see it in the container. If you go up holding the rope when it's tied to the altar you're told you let go of it, unless you have it in a container. In that case you can continue to interact with the rope, although it doesn't show. When you return to Chamber of Ra, the rope is moved there.
10. If you're holding an unlit match, then LIGHT TORCH lights the torch without lighting the match.
11. If you're holding a lit match, you can LIGHT or BURN something flammable WITH MATCH even if it's not there.
12. The implementors went to great lengths to avoid having to keep track of more than one match at a time: dropping a match makes it disappear, after you've used a match you automatically drop it, and PUT MATCH IN anything is treated as DROP MATCH. However, you can THROW MATCH, and it stays there. You can't pick it back up, but if you take another out of the matchbook, the one you threw disappears. If you THROW a lit match, it just disappears when it burns out, with no explanation of where it went. You're also notified when the match burns out, even if you've left that location.
13. If you're wearing the knapsack, THROW KNAPSACK drops it, but many commands think you're still wearing it. You still can't OPEN KNAPSACK, and GET KNAPSACK says, "You already have it.", but WEAR KNAPSACK picks it back up. DROP KNAPSACK or REMOVE KNAPSACK says, "You take the knapsack off and place it down. As it settles, the cover flaps open. You're not carrying the knapsack."
14. SHAKE MATCHBOOK, when it is open, says, "All of the objects spill onto the sand." This is a bug with many strange effects. The room description says, "There is a few matches here." Shaking the matchbook again says, "There's nothing in the matchbook." Examining the matchbook says, "The matchbook is empty." However, you can still count the matches or get a match, both while holding the matchbook and while in the place where you shook it. If you are there without the matchbook, you can only refer to the matches with the word MATCH. If you use MATCHES, it says, "You can't see any matches here!". If you aren't there but have the matchbook, saying COUNT MATCH gives, "You have a weird sense of counting!", but COUNT MATCHES works. You still only have a total of 19 matches; they aren't separate supplies of matches. If you use up 18 matches, the description changes to "There is a single match here." If you use up all 19 matches, the single match disappears, but GET MATCH then gives no response at that location, the first time you try it. If you BURN MATCHBOOK, the matches on the floor are still there, but you've used up 2 (3, including the one you lit). If you BURN MATCH you use up 2 more. When you light a match with the matchbook open and it catches fire, COUNT MATCH says, "You have -1 matches." The room description still says, "There is a few matches here.", but GET MATCH gives no response there, ever after. Alternatively, you can spill the matches using BURN MATCHBOOK; you get, "The matchbook catches fire and is consumed. Whatever was inside the matchbook falls into the pit." Since the matchbook is gone, the only buggy result of spilling them this way is no output the first time you try to take a match after they're all gone.
15. You don't have to be holding the matchbook, or even in the same location as it, to light a match and make the open matchbook catch fire.
16. If you are holding a match and the open matchbook, then COUNT MATCH asks, "Which match do you mean, the match or the few matches?" ("...the single match or the match?" if there's only one left in the matchbook). Answering MATCH repeats the question. Answering FEW or FEW MATCHES produces, "You can't see any   here!". Strangely enough, answering SINGLE counts the matches in the matchbook. In fact, COUNT SINGLE works just fine. THROW MATCH asks the same question, but there's no way out; FEW, FEW MATCHES, or SINGLE all give, "You don't have that.", and MATCH of course repeats the question.
17. When you light a match and the open matchbook catches fire, a couple of turns later you're notified, "Your match went out." In the meantime, you can't see a lit match, it doesn't show in your inventory, and you can't do anything with it.
18. You can EXAMINE MATCH anytime in the game, regardless of where you are or how many matches are left. Normally the message is, "I see nothing special about the match.", even if you see no matches. If you haven't spilled the matches and are holding the open matchbook, or if you are where you spilled the matches, the message depends on how many matches are left. If 1, it says, "I see nothing special about the single match." If 0, it gives the normal message if you didn't spill them. If you are where you spilled them and there are 0, you get the "single match" message. Otherwise the message says, "I see nothing special about the few matches." (even if there are -1 matches!) Apparently, the only way to get the message, "You can't see any match here!" is to be holding the burned matchbook before getting the message, "Your match went out."
19. If you're holding the open, full canteen, you can DROP whatever's in it, leaving the "quantity of water" (or sand) on the floor. Now you can POUR it to make it disappear, whether or not you have the canteen, but if you POUR it ON something you get, "You'd better open the [name of the room] first."
20. Anytime the rope is visible, you can THROW ROPE in one of the four cardinal directions and get the message about it descending into the staircase.
21. PUT something IN ROPE says, "The rope descends into the rope.", and the rope is dropped on the floor.
22. If there is no oil left in the jar, then LOOK IN JAR claims, "The jar is empty.", regardless of any objects you've put in it.