Unsolvable level because game engine differ from original

[ZX-Dash]

Came across on the Internet at your good game. Nostalgia...
Immediately began to pass a set of classic levels (classic_boulderdash)
All solved,
but one level set me to discomfit and i decided to find out what's the snag.

Level 82 (classic_boulderdash) aka Cave C at skill level 5 (ZX Spectrum)

Originally, boulder marked "1" falls first, (because lower placed, i think).

Cave C at skill level 5 (ZX spectrum version) 2 steps marked (level 82 in RnD version)

Using RnD same boulders, first falls boulder marked "2",
so the level becomes impassable

level 82 in RnD version, 4 steps marked

By the way, this and some others "features" slightly facilitates the passage of some other levels
If possible, let me know if there is a way to change the rules of behavior of objects closer to the original.


to see how it works properly:
attached original C5 level solution (ZX) (RZX record)
bdash_zx_level-C5.zip
to playback need an emulator with RZX support
SpecEmu, EmuZWin or something like this
http://www.worldofspectrum.org/emulators.html


and... when i tried to solve or override this, i found some bug...

[Holger]

Yes, you're right. This is a problem when playing Boulderdash (BD) style levels, and the problem in level 82 you described is the prototypical case for the specific properties of falling objects in the R'n'D engine and the original BD engine. As I had plans to integrate also a 100% compatible game engine for BD style levels, this would solve the problem described, but until then, the problem persists and may prevent those levels from being solvable.

But there is indeed a possible solution already built into the standard R'n'D game engine (used for playing BD style levels), and that is "scan mode", which can be set to either "normal" or "reverse" using custom elements (CEs). When set to "reverse", BD style levels should behave more like the original game, and indeed the boulders from your screenshots fall correctly when adding a CE to the level with change options set to "element changes to <empty> after 0 seconds" combined with CE action "set scan mode = reverse" in the level editor. In this case, such a CE could be hidden invisibly in the level border (using the graphics of the border's wall).

To not have to add such a CE for each and every BD style level, I could add a new game engine setting like "Rocks'n'Diamonds (BD)" to the level editor, which would then use the normal R'n'D game engine, but would also enable reverse playfield scan mode (and maybe some other game engine options that would help to come closer to the original BD behaviour).

I could then re-create (convert) the classic BD level set again, and all levels would use the reverse scan mode.