Layers Guide: All 11 Depths
Navigate all Casualties: Unknown layers, from Gravel Lands to Crimson Ascent, with hazards, modifiers, and prep tips.
Casualties: Unknown layers are not just scenery for a digging game—they are the run’s pacing, risk, and resource rhythm. If you understand how the 11 Casualties: Unknown layers change hazards, lighting, enemies, and modifiers, you can pack smarter, route faster, and avoid deaths that have little to do with skill. This guide maps the full descent, the generation numbers that shape each run, and practical prep for every biome, while keeping ending spoilers to what affects planning.
How Casualties: Unknown Layers Work
The 11-layer structure is the core of every run: you descend through ordered biomes, each 307.2 meters tall, then finish with an ending sequence. Each of the 11 Casualties: Unknown layers has its own tiles, structures, traps, enemies, and items, so a route that works in the Gravel Lands will not automatically work later. With Endless enabled, reaching the cargo in layer 10 sends you back to the Gravel Lands instead of ending the run, and the descent continues until you die.
Layer generation is not fully predictable. A modifier has a 40% chance on the Tough preset, the default, and that chance can be changed in run settings. Layer 10 never receives a modifier. Trap and item density also changes by layer by default, and you can adjust those amounts from the main menu before starting.
The scale is deliberately hostile. One block measures about 0.30 by 0.30 meters, and gravity is 16.5 m/s², a bit less than twice Earth’s. That makes long falls and knockback more punishing than the blocky visuals might suggest. At the bottom of a layer, the save/continue prompt disables jumping until you choose an option; a jetpack can lift you off the floor, but it does not clear the prompt or restore jumping.
| Run fact | Value | Planning impact |
|---|---|---|
| Layers per run | 11, then ending | Expect a long descent |
| Layer height | 307.2 m | Vertical routes matter |
| Modifier chance on Tough | 40% | Prepare for extra danger every few layers |
| Layer 10 modifier | Never | Cargo layer has no modifier roll |
| Block size | 0.30 m | Small gaps and falls add up |
| Gravity | 16.5 m/s² | Falls are deadlier than they look |
| Endless cargo behavior | Returns to Gravel Lands | Cargo layer becomes a reset point |
Layer Order at a Glance
The Casualties: Unknown layers order tells you what kind of mistake is waiting next. Use the table as a scouting sheet: the theme and main threats are more useful than memorizing every tile.
| # | Layer | Theme | Main threats to watch | Prep takeaway |
|---|---|---|---|---|
| 1 | Gravel Lands | Cold caverns | Shade crawlers; geysers, jump pads, spike traps | Short falls, scaffolding, and ropes; learn the basics |
| 2 | Deeper Gravel Lands | Darker continuation | Barbed fences, bear traps, cave tick swarms | No background light; concrete beams replace wood |
| 3 | Dried Desert | Sand and hard stone | Turrets, coils, stalactites, landmines, wall biters, shade crawlers | Tall drops and oil make mistakes costly |
| 4 | Wasteland | Radioactive fallout | Sound cannons, toxirock, spent fuel | No enemies, but hazard routing matters |
| 5 | Overgrown Depths | Jungle | Skullcrushers, grabber plants, thornbacks, ticks, elder thornbacks, wall biters | Food is abundant; enemy pressure is not |
| 6 | Frozen Chasm | Ice | Cold, snow striders, gunmines, icicles, ice stalagmites | Rotate heat sources to avoid hypothermia |
| 7 | Fungal Pools | Fungus | Rain, sawblades, sidestabbers, grabber-shrooms | Sleep in life pods to avoid freezing wet |
| 8 | Crystalline Hollow | Bioluminescent crystals | Manifestations, large drops, crystal effects | Inspect crystals and clear corpses |
| 9 | Geothermal Vents | Heat and lava | Lava geysers, lava lamps, pistons, sawblades, drones, tentacles | Manage heat; use coldpuffs for relief |
| 10 | Where We Must Reach | Deepest cargo layer | Drill pod power objective | Cargo and drill pod define the finish |
| 11 | Crimson Ascent | Red overgrowth | Drill pod failure, vertical climb | Exit is at the top; climb on foot |
After layer 11, breaking through the top triggers a surface cutscene. A pod takes you to the lab; carrying the M.E.R.C. scarf changes that outcome to the Mercenary ending. Those endings are separate from the descent itself, but the scarf choice is worth knowing before the final climb.
Modifiers, Settings, and Run Planning
Casualties: Unknown layers modifiers are the biggest reason two runs can feel different at the same depth. The 40% Tough-preset chance is high enough that you should expect extra danger roughly every other layer, but not so high that you can plan around a guaranteed modifier. Layer 10 is the exception: no modifier there, so the cargo layer’s challenge comes from its layout, drill pod objective, and whatever you carried down.
| Setting or quirk | What happens | How to use it |
|---|---|---|
| Modifier chance on Tough | 40% per layer | Pack flexible tools; do not over-specialize |
| Layer 10 modifier | Never | Treat the cargo layer as modifier-free |
| Trap/item density | Changes by layer; adjustable in main menu | Tune challenge before the run |
| Bottom-of-layer prompt | Jump disabled until save or continue | Land, decide, then move |
| Jetpack at prompt | Can lift you; prompt remains | Do not rely on it to skip the choice |
| Liquids at layer bottom | Disappear | Do not depend on liquid at a transition |
| Items at layer bottom | Do not disappear | Dropped gear is less likely lost |
| Tutorial overlap | Structure can remain if you continue into another layer; save and reload removes it | Be aware if tutorial traps mix with layer hazards |
Endless runs change the route rather than the layer list. With that setting on, reaching the cargo in layer 10 sends you back to the Gravel Lands instead of rolling the ending, and the run continues until death. That makes the cargo layer a reset point: your late-run supplies and route knowledge matter, but the descent will not stop at the usual finish.
Layer-by-Layer Prep Priorities
For Casualties: Unknown layers runs, prep should match the hazard type, not just the biome name. The table below condenses the most practical adjustments.
| Layer group | Prep focus | Why it matters |
|---|---|---|
| Gravel Lands and Deeper Gravel Lands | Learn rope and scaffolding routes; check for ticks and traps | Short falls early, but darkness and fences raise risk later |
| Dried Desert | Scan for turrets, coils, stalactites, and landmines; plan oil escapes | Tall drops and viscous oil punish panic |
| Wasteland | Route around sound cannons, toxirock, and spent fuel | No enemies, but standing in the wrong place is the threat |
| Overgrown Depths | Use abundant food and sap; keep space from thornbacks and ticks | Food is easy; enemy contact is the real drain |
| Frozen Chasm | Rotate between Ion space heaters, heatferns, and life pods | Cold is the main danger; hypothermia kills |
| Fungal Pools | Sleep in life pods; watch sawblades, sidestabbers, grabber-shrooms | Rain plus wet sleep can freeze you |
| Crystalline Hollow | Inspect crystals; clear Manifestation corpses fast | Crystal effects and corpse chains create chaos |
| Geothermal Vents | Manage heat; watch fake crates and wall tentacles; use coldpuffs | Lava, heat, and freezing beams punish slow reactions |
| Where We Must Reach | Secure cargo; solve the drill pod power requirement | The drill pod needs a strong power source to carry you back up |
| Crimson Ascent | Climb to the top; expect the pod to break | The exit is above, not below |
- Dried Desert: Oil is more viscous and harder to escape; fractures and exhaustion can turn a bad route into drowning. Use sand vines like climbing ropes and look for Rose lights, but treat recharge stations as suspect because they are frequently flooded with oil.
- Frozen Chasm: Use Ion space heaters, heatferns, and life pods as warm points. Do not push into the cold without a return plan, and watch for snow striders and gunmines while you rotate.
- Fungal Pools: Sleep inside life pods when wet; the constant rain can freeze you. Fungali bungali is documented only here and can be broken for bunchunk to craft procoagulant.
- Crystalline Hollow: Kill Manifestations near safe ground, then eat or destroy corpses quickly; leftovers can become two more. Bigger groups are slower, so do not let them snowball.
- Geothermal Vents: Treat container crates as suspect; some drones disguise themselves and fire a freezing beam. Wall holes can hide tentacles that drain blood. Break coldpuffs when you need cooling.
- Where We Must Reach: The drill pod needs a strong power source, and it carries you back up after you secure the cargo. In Endless, the cargo sends you to the Gravel Lands instead.
- Crimson Ascent: The drill pod breaks on arrival, so the final climb is on foot. The sky is golden, or grey if you carry the M.E.R.C. scarf.
Crystalline Hollow Crystal Effects
In Casualties: Unknown layers, the Crystalline Hollow is the layer where curiosity can kill you. Most crystals are ordinary, but some carry one or more properties. Examine special crystals up close before touching; crystals with several properties look visibly distorted. Tiny crystals and crystals near the layer entrance never have properties.
| Crystal property | Effect |
|---|---|
| Healing | Heals the body once when touched |
| Fragile | Shatters when touched |
| Gravitational distortion | Pushes away or pulls in anything nearby |
| Electric | Shocks and knocks over whoever touches it |
| Burning | Is on fire and burns whoever hits it |
| Thermal | Heats or cools its surroundings |
| Septic | Causes sepsis to anyone who stays near |
| Unstable | Ticks when touched or hit, then explodes |
| Animated | Releases one or two Manifestations when touched or hit |
| Positional instability | Teleports whoever touches it to a random nearby spot |
| Melting | Drips groundwater or lumalgae |
| Kinetic | Shakes and flings whoever touches it away |
| Electromagnetic | Pulses when touched or hit, draining battery charge |
| Bright | Extremely bright |
| Metamorphic | Shimmers, is very durable, flashes when touched, and breaks into one to three random items |
| Mimic | Swaps places with another nearby crystal when touched |
| Radioactive | Gives off radiation |
Practical reads: Healing is a one-touch heal, so save it for real damage. Fragile shatters on contact; Unstable explodes after ticking; Animated releases Manifestations; Electric shocks and knocks you over; Radioactive gives off radiation. Thermal can heat or cool, and Melting supplies groundwater or lumalgae. If a crystal looks distorted, assume multiple effects and inspect from a safe distance.
FAQ
How many Casualties: Unknown layers are there?
There are 11 Casualties: Unknown layers, followed by an ending sequence. Each layer is 307.2 meters tall, and layer 10 is the cargo layer.
Do Casualties: Unknown layers always have modifiers?
No. The modifier chance is 40% on the Tough default preset and can be changed in run settings. Layer 10 never has a modifier.
What happens at the bottom of a Casualties: Unknown layers descent?
You get a save/continue prompt, and jumping is disabled until you choose. Liquids that touch the bottom disappear, but items do not. A jetpack can move you, but it does not remove the prompt.
How does Endless mode change the layer route?
With Endless enabled, reaching the cargo in layer 10 sends you back to the Gravel Lands instead of ending the run. The run continues until you die.
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