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[File] Jet Set Willy - Mildly Patched


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Jet Set Willy - Mildly Patched


JSW1 for the Spectrum with a few mild patches present.

 

Care was taken to avoid over-doing any fixes with a few exceptions. The intention being to try to retain reasonable originality but taking a mild twist on the regular '4 poke' fix:

 

1. The Basic loader was slightly altered (see screenshot) , the embedded codes for the flashing and colour blocks were replaced with their instruction counterparts. Care was taken to ensure the ordering was kept the same. The 'crash' poke was left intact but the real floating point value was changed from 23613 to 16384, thus ensuring the 'crash' poke did not have any effect as it was now just setting the first byte in the screen memory to 0 harmlessly. The combi-screenshot shows both original with 'exposed' embedded values and the 'replacement' one. Viewing them in 128K Basic they look about the same, the change is only really apparent in 48K Basic mode, however they function identically with the exception of not crashing if Break is pressed.

 

2. The keypad routine was left intact however rather than change the first JPZ or the second JPZ to just a JP (to always pass the keycode) the reset the machine instruction was changed to start the game instead by just changing 00000 to 34762. This way if both key code entries fail, the code falls though to the 'reset' line but its now going to jump to the title screen instead. This also preserves both calls to the keypad code too, so that both instruction strings are seen.

 

3. As per the official bug fix, the fire cell was removed from the Conservatory Roof. Viewing this screen on both JSW2 and on JSW1 and JSW2 on several other platforms, there is a mild variation in how it is fixed on those, generally it involves removal of one more fire cell but in this case, the single cell removal (although not perfect by any means) was felt sufficient.

 

4. As per the official bug fix, the earth cell in Banyan Tree was changed to a water cell. There are other fixes to this such as modifying the tree 'trunk' and/or the lower 'roots' area however these are a bit too much for a mild bug fix, so the official fix was felt best.

 

5. The self collecting item in Swimming pool, there are various ways to fix this however a fractionally different approach was taken. The most common one is to set the ink to 5 (cyan) however in this case it was set to 4 (green) as this may be a more suitable colour given Orangery is above, aka: a 'Vines' effect and that screen is mostly green too

 

6. The invisible object in First landing, although the official 'fix' moves it, unless further action is taken it is still invisible and it is quite possible to miss it if you are jumping to avoid an arrow. Rather than give it shape/form it was easier to simply remove it from the game.

 

7. The double object on the beach, there are two ways of looking at this. Previously splitting it into two and moving one further to the left so Willy is forced to use the water 'conveyor' seemed ideal however this file is meant to be a mild fix so the best approach here was merely to set it to be just one object not two.

 

8. The pause bug caused by the presence of an Interface1, as per Skoolkids bug fix this was rectified by changing the IN A © to IN A (254) , along with a single NOP for the inactivity counter as well. This does not prevent pause it merely means the game will not auto-pause, the same as if the in-game music is playing.

 

9. The ability for Willy to leap from the top of a rope where he is not intended to such as Beach , On The Roof were rectified by changing his height comparator from 12 up to 15. This usually prevents him climbing high enough to be able to 'jump top exit' while on a rope.

 

10. Thought was given to the guardian halo effect, as well as corrupted conveyors although their fixes involve potentially putting some code into the unused areas, the same as the bug that effects Under The Roof if you happen to fall off. The latter two quirks were ignored and the former 'halo' ones were fixed by simply turning off the bright effect on the few effected sprites.

 

11. The infamous 'attic bug' was rectified using the official method of setting its co-ordinates correctly as this is the most sensible and efficient fix.

 

12. The incorrect animation counter for the Monk/Priest in Chapel as well as the saw in Cuckoo's Nest were fixed by setting them from 03 to 07 and setting their correct starting frames so they animate as intended and do not move 'backwards'

 

13. Unlucky for some ? The slightly annoying effect of the time and item count temporarily flashing back to 000 and 07:00am was rectified by changing their initial display values to be a blank space, leaving the colon intact. This means that they temporarily flick out and back in again however this seems indefinitely preferable to having them appear to have the incorrect values displayed albeit temporarily. There is a small article in our Articles system describing this in detail.

 

14. Finally, the existing bugs/quirks such as jumping from the top of Dr Jones and Watch Tower as well as Esmerelda are left in, as they were in the original file, along with the TRS-Dos code at the end of the file.

 

Enjoy!


 

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