Axis is square-root scaled so the crowded early gates (10–31) get room. Red strip = share of clears with at least one loss on that stage, per build — the walls. IAP packs are counted at the stage the buyer had cleared when buying.
Main quests run in parallel with the campaign: most players who play claim quests 1–42 on their first day, so this track decays far less than the campaign one. Red strip = share of players who claimed that quest but never the next one — where the quest line stalls.
FeatureUnlockData config (41 entries, datamined 2026-10-26): campaign stage, main-quest number, or mine depth. Mine depth (Hero Enhance, Mastery at depth 40) is not tracked in the event data, so it is listed but not measured.level_win reports the stage advanced into, so stage N is cleared at level_win(N+1)). Reached a main quest = claimed that many main-quest rewards (each claim counted once).