Challenges are unlocked by the Adjustment Bureau metaphysics upgrade. They impose special restrictions and give permanent rewards once a certain milestone is reached. They reset your game, with paragon and karma gained as normal.
Chronospheres will not bring over any resources if resetting with one of these challenges, except for Post-Apocalypse (details below). Instead, resources will be placed in reserves and can be reclaimed after the challenge is complete.
As of 22.214.171.124, multiple challenges can be applied simultaneously, and challenges provide stacking rewards for multiple completions. Challenges now have their own game tab, instead of being under science.
Main article: Iron Will
You do not need the Adjustment Bureau and you do not need to enable it in the Challenges menu.
Description: Iron Will is a bit hidden challenge and you don't need to click here to enable it: reset the game and play without kittens.
Unlock Requirements: None
Details: If you made it past Archery and your zebra limit is less than 10, your zebra limit is increased by 1. Your zebra limit will also increase by 1 for every 10k science spent on technologies the previous run, up to a maximum of +100 per run (ie, subject to diminishing returns). This button is same as apply pending and allows to start run without chronospheres/cryochimbers (reserves are created) without starting any challenge run. You can then exit Iron Will at any time by building housing.
Description: Restart the game with only winter seasons. (Catnip will not benefit from paragon production bonus.)
Goal: Get to Helios.
Base Challenge: The four-season cycle is replaced by endless winter.
Base Reward: Weather odds change from normal 65%/warm 17.5%/cold 17.5% to normal 65%/warm 22.75%/cold 12.25%. On average, this constitutes a 1.68% improvement to Catnip Field output.
Increasing Challenge: For each run after the first, cold winters will be 2% harsher and 5% more frequent.
Increasing Reward: For each run completed, the effect of Spring on Catnip Fields and Summer on Solar Farms will be increased by 5%, capped at 200% with diminishing returns starting at 150%.
Description: Restart the game with kittens acting their own way : kittens are lazy, always eat extra catnip and can't be assigned as leaders.
Goal: Build an AI Core
Base Challenge: Kittens always eat extra catnip as if working. Only half of your kittens can be assigned jobs. No kitten may be assigned as leader. Kittens never gain skills.
Base Reward: Kittens count double towards Karma gains when you reset.
Increasing Challenge: For each run after the first, 5% more kittens are lazy.
Increasing Reward: For each run completed, increases skill bonus of Master skill level by 20%, capped at 400% with diminishing returns starting at 300%.
Description: Restart the game with consumption of energy multiply by 2.
Unlock Requirements: Have both energy production and energy consumption.
Goal: Unlock and build at least one of every energy production buildings and space structure.
Base Challenge: Energy consumption is multiplied by 2.
Base Reward: Production penalties caused by negative energy are divided by 2.
Increasing Challenge: For each run after the first, energy consumption will be increased by 10%.
Increasing Reward: For each run completed, energy consumption will be reduced by 2%, capped at 100% with diminishing returns starting at 75%.
Details: Needed buildings are as follows: Steamworks, Magneto, Solar Farms, Hydro Plant, Reactor, Satellite, Sunlifter, Tectonic, HR Harvester
Description: Restart the game without faith bonus.
Unlock Requirements: Void Space
Goal: Reset with at least one cryochamber.
Base Challenge: Order of the Sun is unavailable.
Base Reward: The cap on Solar Revolution will increase by 100 percentage points per Transcendence tier (equivalent to 20 Black Obelisks).
Increasing Challenge: For each run after the first, max culture will decrease by 250, max science will decrease by 500, max catpower will decrease by 125, and happiness will decrease by 0.5.
Increasing Reward: For each run completed, Solar Revolution effectiveness will be increased by 10%, capped at 400% with diminishing returns starting at 300%. This effect is multiplicative with Black Obelisks.
Details: You can still get unicorn religion and cryptotheology. As of 126.96.36.199, the challenge will be successfully completed even if you reset into another challenge.
For versions 188.8.131.52 and earlier: Note that because the win condition is "reset with cryochamber", you must not reset into a new challenge, or the run will not be completed.
Description: Restart the game with a half-life time.
Unlock Requirements: Shatter a Time Crystal.
Goal: Reach year 1000
Base Challenge: Years will not increase normally past the year 500.
Base Reward: Colder combustion of Time Crystal. Each shatter will generate half as much heat.
Increasing Challenge: For each run after the first, the cost to advance time will increase by 0.5 TC and 0.4 void.
Increasing Reward: For each run completed, the cost in TC to advance time will decrease by 2%, capped with diminishing returns. Each completion also increases the cap of the Temporal Press building by 5, which allows for custom shatter amounts. The price ratio of the temporal press also decreases with each completion.
Details: You will have to smash time crystals in order to reach the year 1000.
Note: Void cost is rounded up. Shattering 5 TCs at once costs less void than shattering 1 TC with fractional void cost.
Description: Restart the game with no astronomical events to observe.
Unlock Requirements: leviathans appear.
Goal: Build one Space Beacon (+1 Beacon per completion)
Base Challenge: Astronomical events do not occur.
Base Reward: Elders come early. Acts as a free Black Pyramid. This invisible Black Pyramid acts just like a real Black Pyramid, improving Black Nexus and so forth.
Increasing Challenge: For each run after the first, an additional Space Beacon will need to be built to complete the run.
Increasing Reward: For each run completed, Markers' corruption factor and Leviathan energy cap increase will both be improved by 10%, capped at 200% with diminishing returns starting at 150%.
Details: Some key buildings and space missions have had their initial costs altered so they are possible to obtain without any starcharts.
Description: Restart the game without ability to hunt. Some policies are unavailable.
Unlock Requirements: Send kittens on 1000 or more hunts at once.
Goal: Research Outer Space Treaty policy and reset.
Base Challenge: Hunting is unavailable.
Base Reward: None.
Increasing Challenge: More expensive Embassies(Cost increase by 1), Steamworks(Cost increase by 2) and Policies(Cost increase by 25%, additive), Weapon technologies (Composite Bow, Crossbow, Railgun) are permanently less effective (-10% additive per completion, capped at -100%).
Increasing Reward: Increases trade ratio, see below. Gain +10% Alicorn chance per completion, with diminishing returns starting at 90% and capped at 120%.
Trade Ratio Explanation: The formula is complicated, but basically it either gives you A) a trade bonus as a ratio times the number of trade posts you have, or B) a flat boost to the number of tradeposts; whichever is smaller. The ratio boost begins at 10.65% of your tradeposts and increases linearly by 0.75% per completion, capped at 25% with LDR. The flat boost begins at +10 tradeposts and increases quadratically per completion, no cap.
Note: You can't get fur, and therefore parchment, until you get a mint. To progress you must get a printing press to get the needed manuscripts. With a Temple you can start getting culture, which you can invest in Shark Embassies to speed up your manuscript gains. Unicorns have a small chance of wandering into the village each game day if you have less than 2; this is boosted by time-related effects.
Description: You found a broken timeline with extreme pollution. You can send your strongest kittens to clear this mess. Pollution has more negative effects.
WARNING: you have limited time to establish food production after starting this challenge
Unlock Requirements: Build a Holy Genocide
Goal: Clear all pollution.
Base Challenge: Pollution starts at 10M ppm, kittens arrive slower, catnip fields cost unobtanium at high pollution levels and/or with high numbers of broken cryochambers, natural dissipation of pollution is disabled, and trade gold/catpower costs increase with pollution level.
Base Reward: Increases amount of cryochambers that can be operational. Unlocks special policies for the run.
Increasing Challenge: +1% increase in starting pollution each completion and additional kitten arrival slowdown
Increasing Reward: +1 Cryochamber support per completion. (In other words, your cryochambers will now be capped at Chronospheres + Number of Post Apocalypse completions)
Note: If you have cryochambers, you will bring over kittens and a store of catnip (proportional to the number of kittens brought over and your karma amount). This can be combined with other challenges, but be careful about bringing kittens into atheism or pacifism. Due to their reset requirements, you won't be able to reclaim reserve resources to help fix the cryochambers. This means you'll have to generate all the resources necessary to repair cryochambers within the challenge or some kittens maybe be lost.
This resets your game, with paragon and karma gained as normal.
Chronospheres will not bring over any resources if resetting with one of these challenges.
You can get the resources carried over by chronospheres later in the challenges tab.