Challenges

**Challenges** are specific rule sets that are applied to the next run upon the usage of Portal, which after completion grant a reward to the player.

They can be accessed from the Portal menu. Starting a challenge requires the player to use the Portal. A started challenge can be abandoned at any time from the View Perks menu, which reverts all changes done by the rule set to your current run and lets the player continue normally. The only exceptions are the challenges Scientist, Obliterated and Eradicated, which will force the player to restart the run when they're abandoned.

Challenges have to be unlocked by meeting specific criteria. Once unlocked, a challenge will be available to be started at any time through the Portal menu and can be done any number of times; however, most challenges don't yield additional rewards for multiple completions.

Once a challenge is complete, everything that it affected is returned to normal, which lets the player continue their run without the challenge rules being applied any longer. If the challenge awarded a perk, the perk will be immediately added upon completion, which allows the player to respec and immediately put points into it if they wanted to.

Only one challenge can be active at a time.

## List of challenges

Below is a list of all challenges in the game:

### For U1

Note: The challenge Scientist has multiple tiers. For additional general information on the Scientist challenges, click here.

## Helium challenges

Some challenges award additional amounts of Helium when completed. When the first Helium challenge is unlocked, it becomes inefficient to do runs without running such a challenge, and it is encouraged to always run the best one available.

Helium reward from Void maps will also be increased by the Helium challenge's Helium multiplier if they're completed within the scope of that challenge.

## Radon challenges

Some challenges award additional amounts of Radon when completed. When the first Radon challenge is unlocked, it becomes inefficient to do runs without running such a challenge, and it is encouraged to always run the best one available.

Radon reward from Void maps will also be increased by the Radon challenge's Radon multiplier if they're completed within the scope of that challenge.

## Daily challenges

Daily challenges are special challenges with randomly-generated rules. One new daily challenge is available every day, as the name implies. Each daily challenge can only be run once. Players can choose challenges up to the previous week's challenges, 7 in total.

Daily challenges do not have a specified end point; they only end when the player clicks the "Finish Daily" button under the Bone Trader button, upon which the player will have their Helium/Radon multiplied by an amount depending on the daily challenge's difficulty. As such, all daily challenges are Helium/Radon challenges. **Helium/Radon rewards from daily challenges do not affect He/hr, Rn/hr or Bone Portals.**

The Daily challenge for a given day may be run in either the Helium Universe or the Radon Universe, but not both. The procedurally generated rules of the challenge will differ between the two universes, so it may be helpful to read the description in each universe, to see where you'd like to do it.

## Challenge²

Challenge² is a special set of standard challenges which do not have an end point, and can be repeated infinitely for permanent boosts to health, attack and Helium gain. No Helium is awarded from any source while such a challenge is active. See the Challenge² page for more details.

## Challenge³

Challenge³ is another special set of standard challenges which do not have an end point, and can be repeated infinitely for permanent boosts to health, attack and Helium/Radon gain. No Helium/Radon is awarded from any source while such a challenge is active. See the Challenge³ page for more details.

The bonuses from Challenge² and Challenge³ stack multiplicatively, creating one big Challenge∞ boost to health, attack and future Helium/Radon gain.