IRF

There are other places too in these disassemblies where hexadecimal numbers would be more appropriate than decimal (e.g. the Codes table in JSW), and solving this problem is also on my TODO list for future releases. The tricky part is that the solution must enable me to build either a fully decimal or a fully hexadecimal disassembly from the same source files, with no manual base-conversion work required. I have some ideas about how to do it, but they involve some changes to SkoolKit.
 
In the meantime, feel free to point out other places where the use of base 10 is jarring or inconvenient, and I'll make a note of them. :)

Actually, the fact that arrows can collect items deserves its own trivia entry - I'll add that to my TODO list for the next release. Thanks!
 
In the 'White-seeking missile' entry I hope I've made it clear that arrows don't mix well with anything white, whether it's guardians, wall blocks, floor blocks, nasties etc. The white rope is just a good example of something to be avoided when arrows are around.

Yes.
You can actually put another value into that for a room ID, for instance if you set it at 37 Willy become the 'Flying Pig' in The Orangery instead. :)

Normal Willy?

As I texted to my missus last night from my works do: "Im In Go Messy Christmas!"
 
(Was supposed to be 'Ho Ho Ho Merry Christmas!" - bloody predictive text!! :D )

I just noticed this and thought I'd point out that there's already a screen called 'Under the MegaTree'.  This room is under 'Under the MegaTree'!

EDIT: spoiler!

I also like the additional location on The Beach identified by Spider.  Having just had a go (in the original edition though so there wasn't actually an item there), I can now appreciate the added peril - the conveyor belt in the sea transports you off screen to The Yacht, where you have to have your wits about you and jump before you hit the Nasty flag.

It struck me recently that the authors of Jet Set Willy 2 must have been unaware of the auto-collect item in the Swimming Pool, as there is no such item, auto-collect or otherwise, in the equivalent room in JSW2.  This is apparent from the fact that there's an online solution which takes you through how to complete the game, having collected every item, and the Swimming Pool is the only room in the whole game that you don't need to visit in order to do so.  (Apart from one called 'Cheat', which of course you can't access without cheating!)

Going by this quote, my preferred location for a second object in AtWB doesn't accord with his interpretation of the machine code: "One of the items on The Beach is intended for a different room, but the x-coordinate byte is correct. The y-coordinate may be correct, or may be eight squares too low."
 
I do think I've identified the optimum place to put it from a gameplay perspective though.
 
Also, in terms of x and y coordinates it's not that far off where you put the extra item on The Beach in the 2015 bug fix edition (in the waves)?

We'll have to think of some more tricky locations for items.

(N.B. I've just edited a couple of posts above where I referred to the Swimming Pool when I meant The Beach.  I was mixing up the double item in the original Beach with the auto-collect in SP.)

Going by this quote, my preferred location for a second object in AtWB doesn't accord with his interpretation of the machine code: "One of the items on The Beach is intended for a different room, but the x-coordinate byte is correct. The y-coordinate may be correct, or may be eight squares too low."
 
I do think I've identified the optimum place to put it from a gameplay perspective though.
 
Also, in terms of x and y coordinates it's not that far off where you put the extra item on The Beach in the 2015 bug fix edition (in the waves)?

Thank you for the clarification. :)
 
OK take a quick look at this following your suggestion, I've positioned Willy out of the way for extra clarity:
 

 
This does make perfect sense and I can see what you mean, to coin a phrase "a picture says a thousand words"
 
Also you're 100% correct you *can* escape the conveyor without dying if you time your jump right you can (once you're aware of it) relatively easily escape via a jump.
 
Now, there's a slight issue with positioning this object here. Willy cannot climb down again without losing a life. See pics:
 
Willy in place to collect object after climbing:
 

 
The only way 'down' is right, moving left will result in an infinite death as you'll fall through the screen to the Back Door.
 
Willy moves right to land on the platform below:
 

 
All looks OK, but the 'issue' here is a jump to the left is certain death, a jump to the right results in him exiting the screen at the top, and when he falls, he falls straight onto the razor blade nasty as its start position is too high. For necessity in the pics I've had to immunize him so you can see:
 

 
The conclusion I guess is its quite possible but you must then jump right onto the roof ramp/slope and not attempt to climb down again. :)

By the way, you gave me the idea earlier on in this thread when you said that AtWB was one possible location where the extra Beach item could have been intended for, based on your reading of the machine code?
 
EDIT: Sorry, it was a post by Zub, not one of yours:
 
http://jswmm.co.uk/topic/51-jsw-msx-tatung-einstein/?p=211

Sorry, I didn't mean the vertical ladder (which is halfway across West Bedroom and takes you up to under the eaves of AtWB - mind your head! - where there is an existing object [pair of pliers] to collect, which I believe involves a quick diversion via the bottom-left of West Wing Roof).
 
Rather, I meant to refer to the climb at the left-hand side of West Bedroom which involves tricky left and right jumps before you eventually end up on the outside of the sloping roof of AtWB.  Having an object there (just before the final jump onto the sloping roof) would essentially mean you'd have to ascend the West Bedroom twice - both tricky climbs in their own way - once on the inside and once on the outside.
 
Just to be clear, I'm suggesting putting the object on one of the two short platforms above the word 'the' in the screen title of Above the West Bedroom.

" its a bit like West Bedroom where if you get on to the conveyor on the far right that's a fatal error too."
 
Not if you jump quick enough which allows you to escape onto the platform on the screen above.

Further to the above, I found an old magazine article/map on World of Spectrum which speculates along similar lines (except it suggests there may be an invisible object, and the annotation puts it lower down the ladder in West Bedroom - but it would make more sense from a challenging gameplay point of view to put it at the top of the ladder in Above the West Bedroom, or at least far enough up the ladder to be past the 'point of no return', necessitating the player to complete the climb after collection and then perform the tricky-but-doable jump from left to right underneath the security guard and wobbly jelly):
 
http://www.worldofspectrum.org/pub/sinclair/games-maps/j/JetSetWilly.jpg

Whilst I appreciate your reluctance to add rooms, it strikes me that Matthew Smith, by creating the mysterious Room 47, gave us licence to contemplate one extra room.  So in my Fantasy Version of JSW I would include a modified version of The Belfry to tie in with Rescue Esmerelda, and it would also allow for a lateral exit from the otherwise inescapable trap that you may have inadvertantly designed at the top of the Watch Tower... (see my comment at http://jswmm.co.uk/topic/71-new-2015-ti-994a-conversion-of-jsw/?p=353)
 
Perhaps make it a leap of faith requiring a pixel perfect rightwards jump off the upper platform of Watch Tower, also with a rapid reaction required upon entering The Belfry to avoid a rapidly ascending Quasimodo...  What do you reckon?