The first new level since L2, and the campaign's endurance beat. 7 segments, 6000 units,
63 events, ~10 minutes. Authored entirely from systems that already exist — no new engine work.
The three acts are anatomy, not invention: duodenal bulb -> descending duodenum (the ampulla,
where bile enters) -> jejunum -> deep jejunum -> ileum -> terminal ileum -> ileocecal valve.
Giardia really colonises the duodenum/jejunum and Peyer's patches really concentrate in the
ileum, so the difficulty curve IS the gut's own immune gradient: you fly from the quiet
absorptive end into the lymphoid end and the walls get angrier.
Identity vs L2: flow 8-10 against L2's 12-20, curviness up to 0.70, fog 0.050. L2 punishes bad
reflexes; L4 punishes bad reading. Segmentation ring gates (the small bowel's real motility)
teach at 70% open and test at 43% in an 8-unit lumen.
Three catalogue rows carry the new fiction onto existing archetypes — chyme_clump (floater),
neutrophil_hunter (seeker), bifido_colony (flora). The ileocecal biofilm gate at s5500 is the
first time the reputation loop pays out at a level's END rather than mid-level.
C's own tooling verifies it: selfcheck 4/4 valid, and --sim reports par 600s vs par-pace 576s
("par is reachable at par-pace throttle"), a pressure curve of 1.00/1.43/1.90/2.46/1.65/2.69/
1.63, min clearance 3.62 vs the 2.5 law, all 22 checkpoint gaps <= 29.3s. Driven end-to-end
in-engine: all six entity types spawn, biofilm fires at 5500, valve gate completes to L5.
The GDD's Tapeworm miniboss is not here — no boss framework exists yet. It goes in at ~5500
when that lands; the level notes say so.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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