World & Level Structure

The stack

The retail data ships 24 level folders (level0–level24, with no level9). They are discrete, hand-built volumes connected by fixed transitions, not an open world — the fiction of a fortress bored downward into rock maps exactly onto the technology.

The vertical arrangement does real design work:

Depth reads as difficulty. The player never needs a level-recommendation UI; "further down" is the whole signal.
The city is a hub, not a level. Arx city concentrates shops, quest-givers and safety, so every excursion is a there-and-back with a returning cost.
No fast travel. Distance is therefore a real budget, which is what gives the 3× sell spread its teeth — hauling loot home costs minutes.

Verification status

Level count and the missing level9 are verified from the unpacked data directory. The interpretation of pacing and hub structure below is analysis, not a developer statement.

Persistent world state

Entities carry their state across level transitions and saves — dropped objects stay dropped, opened doors stay open, killed NPCs stay dead. Combined with the script layer, this makes the world feel authored-and-remembered rather than instanced. It also means the player can permanently break quest chains by killing the wrong NPC or losing the wrong object, a cost Arkane accepted here and spent the next decade designing around.

Gating vocabulary

Progress gates are physical or informational, almost never numeric:

keys and levers (physical)
passwords, names and rumours (informational — held in the player's head, not a quest log flag)
lock ratings, checked against Mecanism, with 100 reserved for "never"
runes as spatial rewards, so magical power is placed by level designers

Notably absent: level requirements, stat checks in dialogue, and locked doors that open when a quest flag flips. Arx's gates are things you can attack from several directions, which is the immersive-sim contract.

Open questions

Which level indices correspond to which named regions, and whether level9 was cut or renumbered
Encounter density per level and whether difficulty scales by content or by attrition
How many quest chains are breakable by NPC death — a concrete failure-tolerance audit

Touchpoints

→ Core Loop: the hour-scale loop is defined by hub↔depth travel
→ Stealth & Light: light placement is encounter design
→ Magic & Runes: rune placement is the mage's real progression curve
→ Player Journey: no map markers means orientation is a skill the player builds