IRF

By the way, in your test_fall demo, it looks like Maria has catched up Willy with the last unopened bottle.... what Willy was just going to "tidy up".😆

Thank you for your demos, Spider! They made this very clear! ☺️Thank you, too, IRF, for the fun fact! 🙂I think there should be lots of toilets positioned in every room in every JSW game to save Willy falling too far!😋

And a quick demo, no player interaction needed other than to start the game:
test_fall.tap
 
Same 'base' as the other two test files, ie: OK for editing for testing not really recommended for building a whole game from.
EDIT... Updated very slightly, now Willy has the choice of moving left to collect the single (wine bottle) item from Top Landing or go to rightwards to explore.
A little care should be taken with when he grabs the item with regard to the descending razor blade guardian! However if he does lose a life, upon re-materialisation he'll clear it on his automated run.

Fun(?) fact: if you extend the Bathroom ramp all the way down to the floor, and put a hole in the upper platform directly above the toilet, then during the toilet run Willy will run up the ramp and drop through the hole... But will disappear halfway through the fall... then appear suddenly in the toilet. (ie Without visibly falling through half of the height of the room.)
This is because the code which tests for Willy's coordinates at the end of the toilet run doesn't check which vertical half of the room he is in.

(But of course, when he is eventually drawn with his head down the toilet, he is in the correct location - bottom-right corner, bottom half of the Bathroom.)

Fun(?) fact: if you extend the Bathroom ramp all the way down to the floor, and put a hole in the upper platform directly above the toilet, then during the toilet run Willy will run up the ramp and drop through the hole... But will disappear halfway through the fall... then appear suddenly in the toilet. (ie Without visibly falling through half of the height of the room.)
This is because the code which tests for Willy's coordinates at the end of the toilet run doesn't check which vertical half of the room he is in.

Fun(?) fact: if you extend the Bathroom ramp all the way down to the floor, and put a hole in the upper platform directly above the toilet, then during the toilet run Willy will run up the ramp and drop through the hole... But will disappear halfway through the fall... then appear suddenly in the toilet. (ie Without visibly falling through half of the height of the room.)
This is because the code which tests for Willy's coordinates at the end of the toilet run doesn't check which vertical half of the room he is in.

(But of course, when he is eventually drawn with his head down the toilet, he is in the correct location - bottom-right corner, bottom half of the Bathroom.)

Fun(?) fact: if you extend the Bathroom ramp all the way down to the floor, and put a hole in the upper platform directly above the toilet, then during the toilet run Willy will run up the ramp and drop through the hole... But will disappear halfway through the fall... then appear suddenly in the toilet. (ie Without visibly falling through half of the height of the room.)
This is because the code which tests for Willy's coordinates at the end of the toilet run doesn't check which vertical half of the room he is in.

It does. A number of games are only toilet-completable thanks to this feature.

Doesn't pressing P during the toilet run stop him in his tracks? 

Doesn't pressing P during the toilet run stop him in his tracks? 

The ability to slow the game down would be useful for the room 'The Garden' in JSW2 [original version], the crossing of which requires a succession of well-timed, pixel-perfect jumps.  :o

I just had a thought - is it theoretically possible to complete the original Jet Set Willy without applying any POKES, not even the four officially released ones?
The Attic Bug corrupts the game data and code in unpredictable ways, so unpredictable that the effects are different every time you play the game. Might it be possible in theory that one effect could be to corrupt the list of guardians in both Conservatory Roof and First Landing, creating an arrow which passes along the character row where the items are located in each of those rooms (an invisible item, in the latter case).
Were that to happen, then the white INK of the arrow would auto-collect the items that otherwise can't be collected without using the official POKES, and so the unPOKED game could in theory be completed (provided Willy can manage to complete his journey through the corrupted mansion without one of the many other side-effects of the Attic Bug getting him!)

The walkthoughts were possibly (likely?) mine, I've done several.
Certain rooms however when the bug is in effect do seem to make it deteriorate a bit faster, notably "Inside the MegaTrunk" , staying here and switching emulation speed up a bit (200% is fine) you'll see the status bar start to corrupt. Kitchens can have a similar effect, although the guardians moving horizontally at that stage is erm distracting.
 
A sidenote about the other "big three" bugs: I think half or most of the battle is Banyan Tree, if it were possible to jump from the left side and catch onto a water cell without hitting a guardian, you could then climb it. The "First Landing" object something would have to be done or the item count adjusted to ignore it, same perhaps as "Conservatory Roof"

I just had a thought - is it theoretically possible to complete the original Jet Set Willy without applying any POKES, not even the four officially released ones?
The Attic Bug corrupts the game data and code in unpredictable ways, so unpredictable that the effects are different every time you play the game. Might it be possible in theory that one effect could be to corrupt the list of guardians in both Conservatory Roof and First Landing, creating an arrow which passes along the character row where the items are located in each of those rooms (an invisible item, in the latter case).
Were that to happen, then the white INK of the arrow would auto-collect the items that otherwise can't be collected without using the official POKES, and so the unPOKED game could in theory be completed (provided Willy can manage to complete his journey through the corrupted mansion without one of the many other side-effects of the Attic Bug getting him!)

The corrupted guardians can cause corruptions themselves, but in an unpoked game Willy would just instantly die on entering those rooms preventing the enemies from corrupting the game further. The cheat POKEs in the video I saw were to prevent deaths from guardians, allowing them to cause further corruption.

Could it be possible that those cheat Pokes have corrupted the corrupted parts even more?

The effects aren't unpredictable and aren't different every time you play - the arrow's trajectory is consistent and writes to the same bytes every time.
To be precise, it corrupts the flying bird, UFO, Esmerelda, giant head, skull, sunflower, and Andre enemies, and any room those enemies can be found in result in the guardians being misplaced and (depending on the room) embedded into walls (which automatically kills Willy on room entry). None of those enemies can be found in First Landing, The Banyan Tree, or Conservatory Roof, the rooms that would need changes in order to make completion possible.
It's possible to complete Jet Set Willy without fixing the Attic bug, though - you can apply the other three POKEs (42183,11; 56876,4; and 60231,0), play the game as normal making sure to only climb the East Wall and get the items in Priests' Hole and Dr Jones and head into the Attic once you have all of the other items. From the Attic, you can go Under the Roof -> Conservatory Roof -> Orangery -> Swimming Pool -> Banyan Tree (left to right - not easy!) -> The Nightmare Room -> First Landing -> Top Landing -> Master Bedroom and complete the game.
You can't complete it twice though, because the rooms with those enemies in don't become accessible again even after beating the game.

The internal contradiction in the statement did occur to me (JSW vs MM), but then I suppose the in-game tune in Manic Miner doesn't play during the portal air countdown*, so in that sense it doesn't play continuously.
(*Except in Manic Mixup. 😉) 

I just saw this on a Facebook post:
"MATTHEW SMITH!
The creator of Manic Miner and Jet Set Willy.
Seen back when he was writing games, and then around 2013.
Jet Set Willy was the first game to include continuous music (such as music was on the Spectrum) while you played the game, a feat which up to that point was thought to be impossible.
He actually wrote Manic Miner on a Tandy TRS-80."
It got me wondering - is that claim in bold actually true?

Manic Miner's (maybe) the first to have in-game music on the Spectrum, but obviously there are a fair few arcade games that did it earlier; while I suspect everyone here is aware of that I do see it often claimed as though it's the first game ever to do it on any platform, when it clearly wasn't. Rally X is probably the best example of an arcade game doing it earlier:
I can certainly believe it was the first game on the Spectrum to have in-game music though - it was fairly early on in the Spectrum's lifespan and music in games wasn't as ubiquitous at the time.
The part of the claim I doubt is the "thought to be impossible" part - I'm pretty sure the music in Space Invaders is done exactly the same way as Manic Miner does it, and as much as Matthew Smith did a great job with the game design he wasn't the most amazing programmer in the world, at least not at the age of 17, and plenty of others would surely know it to be possible. I imagine most simply chose a higher framerate over trying to have something somewhat resembling music playing; after all, if you want in-game music you have a tape player attached - just play it yourself.
As for the "plays continuously" comment, I suspect it means as opposed to something like Virtua Racing, where short jingles play at checkpoints but leaves periods without music, or Road Blasters, where the music only comes in towards the end of each level. I doubt it's claiming the air countdown doesn't count and has simply confused the two games.

🙂 
No, because Manic Miner was first by a fair way (a year or just under I think) which discounts the "JSW First" part of it. 🙂
I'm also not convinced at all it was the first game to have an in-game tune that "played continuously" during play either, but I would need to research that to find an 82 or early pre-June*** 83 game that did. It could be the first ZX game to do this but as said I'm not convinced.
*** I'm only about 90% sure on that month, the Software Projects re-release of it was late 83
 
 

I just saw this on a Facebook post:
"MATTHEW SMITH!
The creator of Manic Miner and Jet Set Willy.
Seen back when he was writing games, and then around 2013.
Jet Set Willy was the first game to include continuous music (such as music was on the Spectrum) while you played the game, a feat which up to that point was thought to be impossible.
He actually wrote Manic Miner on a Tandy TRS-80."
It got me wondering - is that claim in bold actually true?

If it helps, this is using the original game, not the highscore challenge version; I just put it here since it's highscore-related. Finding the maximum total score (without dying) was an interesting challenge in itself. On top of the "improvements" I shared before (all of which are also in this run) I managed to score 1863 points in The Vat; unfortunately it wasn't feasible to do this and also reach the maximum total score in the same run due to the life count.