The roster is the alphabet: the sequence is the zombies themselves

Oliver's insight, and it retires a whole subsystem: "we don't need colors at
all! we already have different zombie types.. so the sequence is the zombies
themselves".

The bib and then the ground disc were both inventions bolted on to give a
body an identity it already had. A brute does not look like a runner, the
game is built on reading those silhouettes at speed, and the strip can show
the body's own walk frame instead of a swatch — no legend, no mapping, no new
art ever. It also deletes the accessibility problem outright rather than
deferring it, because a silhouette is not a hue. DRILL_COLS, drawColourRing,
drawBib, PIP_FACES, blip(), drillRingR and drillTones are all gone.

Two rules keep a type unambiguous: the plain shambler is never in the
alphabet (it is what the eaters are, so "not the puzzle" needs no marking),
and one of each type is on court at a time.

The new failure mode this created is instructive. Types move at different
speeds and drill bodies hold their lane, so one in a lane you are not in
walks the whole court and off the back untouched — stranding the sequence
asking for a body that no longer existed, i.e. the un-winnable state the mode
exists to prevent, reintroduced by a change that looked cosmetic. A batch
body crossing your baseline counts as caught now ("GOT PAST YOU"), which is
also just better design, and the speed spread is narrowed to 1.35..0.70 so a
batch stays coherent. Their real difference is HP and that is untouched: a
runner is one shot, a roller is seven.

Verified: 14400 frames of simulation, zero frames where the sequence named a
body that was not on court.

29 tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/zombies.js

@@ -493,7 +493,7 @@ function killZombie(i, quiet) {
   //   and no early return, because everything below is the DEATH — the blood decal, the pile, the
   //     particle burst, the splat and the headshot crack. The first cut returned here and bibbed
   //     bodies died silently and cleanly, which is not what this game does to anybody.
-  if (G.drill && zb.bib !== undefined) drillKill(zb);
+  if (G.drill && zb.drill) drillKill(zb);   // `drill` marks a batch member; eaters are never flagged
   if (zb.variant === 'B') bossDeath(zb); // before endBossFight below, so the card can wait on it
   if (zb.variant === 'o') { popBarrel(zb); return; } // a container: it pays out and scores NOTHING
   if (zb.variant === 'm') { // furniture, not a body: no blood, no mound, no mop boy
@@ -1196,7 +1196,16 @@ export function updateZombies(dt) {
       }
     }
     if (Math.abs(zb.x - faceX0) > 0.004) zb.face = Math.sign(zb.x - faceX0); // sticky: a body standing still keeps facing where it last walked
-    if (zb.z >= COURT.L + 0.7) { aside('ump_unsportsmanlike', 0.5); zombies.splice(i, 1); if (G.mode !== 'eaten' && !G.horde && !G.clearing) splatPoint('O'); } // it reached your baseline (during a mop-up, a straggler that reaches the line just despawns — no point for them)
+    if (zb.z >= COURT.L + 0.7) {
+      // A BATCH BODY THAT GETS PAST YOU IS A FAILURE, not a free despawn. Drill bodies hold their
+      // lane, so one in a lane you are not standing in walks the whole court and off the back
+      // without ever touching you — and since the sequence names it, the round is left asking for a
+      // body that no longer exists. That is the un-winnable state the whole mode is built to
+      // prevent, and it only appeared once the roster became the alphabet: types move at different
+      // speeds, so the runner leaves long before the roller. It counts as caught.
+      if (G.drill && zb.drill) { zombies.splice(i, 1); drillCaught('GOT PAST YOU'); continue; }
+      aside('ump_unsportsmanlike', 0.5); zombies.splice(i, 1); if (G.mode !== 'eaten' && !G.horde && !G.clearing) splatPoint('O');
+    } // it reached your baseline (during a mop-up, a straggler that reaches the line just despawns — no point for them)
   }
 
   for (let i = pellets.length - 1; i >= 0; i--) { // gun rounds flat and fast; lobbed ones ride an arc