The site already has one Raiders of the Lost Aisle — a Christmas Eve toy-department heist. This is a second, separately-built game under the same title and the same isometric-engine idea, with a different story: it's Bank Holiday Monday, the discount shelves are down to the last few tins, and legend has it Aisle 13 — sealed off since the Great Stocktake — still holds one final, impossibly cheap prize. Security guard Big Dave does not share your enthusiasm for bargains.
Both games place every object at a map position (x, y, height)
and project it onto the screen with the same dimetric formula: screen X from
the difference of the two ground axes, screen Y from their
sum, minus height. Rooms here are an 8×8 (Aisle 7) and a
6×6 grid (Aisle 13, the lost one), each object a small box drawn as two
stacked rectangles — a dark "base" at ground level and a bright "top"
shifted up by its height — everything sorted back-to-front each frame
by ground position so a shopper walks convincingly behind a shelving unit
without any real 3D renderer involved.
This game has its own headless test suite (test_raiders2.py,
built the same way as the rest of this site's Z80 programs: boot it, drive
it through real control flow via z80mini.py, assert on outcomes,
render the screen to PNG). Every logic assertion passed well before the game
actually looked right. Three separate bugs only showed up once the renders
were actually opened and looked at:
$3D00 — which works fine on real hardware and in a
full emulator, but z80mini.py is a from-scratch
interpreter with no ROM image loaded at all, so every glyph read came
back as zero. No crash, no failed assertion — a bare black
screen. The fix was switching to this codebase's own bundled 8×8
font (fontdata.inc, the same one the other programs here
use), which lives in the assembled program itself and doesn't depend
on anything being loaded at a fixed ROM address.dec bc / ld a,b / or c — which
overwrites A with the remaining countdown value. The very
first byte in each row wrote a correct zero; every byte after that
wrote whatever was left of the countdown instead, producing a
decaying stripe pattern of stale pixel garbage under the next room's
freshly-drawn floor. This is the same bug class flagged elsewhere in
this codebase — a routine silently clobbering A as
a side effect of something that looks unrelated — just a fresh
instance of it. The fix doesn't route the fill value through
A at all: ld (hl),0 writes the constant
directly, leaving A free for the loop's own bookkeeping.
Getting caught sends the shopper back to Aisle 7's entrance, drops the tin if they were carrying it, and starts that grace period. Reach the checkout with the tin in hand and the till rings up a win.
pasmo --tapbas raiders2.asm raiders2.tapThe chip inside your Spectrum also ran Pac-Man, half the arcades of the 1980s, the Sega Genesis's sound, and — through a direct descendant — is still inside graphing calculators being sold today. A plain-English guide to the Z80's 48-year career.
Every Spectrum program you've ever typed says OUT 254 or IN 254. The ULA doesn't actually check for 254 — it barely checks anything at all. A tiny program proves it, live, on screen.
I set Claude Code loose on a ZX Spectrum game with $100 of credits and the new Fable model, expecting a doddle. Here's why 48K of 1982 hardware humbled it in ways a modern REST API never could.