This mode is commonly used for testing features that are planned for future updates. It can be opened by clicking on the Red Forest logo 3 times at the main menu once and then typing a password. Doing so will send the player to a game screen with a different background. Each version of Red Forest may also have differences in the initial state of the Experiment Mode farm.
The Experiment Mode screen can be reset by pressing F3.
Each version of Red Forest uses a different password for Experiment Mode.
Version 0.4.X
In Version 0.4.X, the password is OCICAT,
dedicated to a friend who reminded Alexander of the project which had sparked the return of the project.
Version 0.5.X
In Version 0.5.X, the password is HAYAMI,
named after Hīrā Hayami; one of Alexander's many supportive art friends.
TrueClear
For testing True Clear feature.
GetAchievement
Input: Achievement ID
Returns whether the achievement had already been achieved or not.
SetAchievement
Input: Achievement ID, Boolean
Sets the status of an achievement, 0 being unachieved and 1 being achieved.
SetCash
Input: integer
Sets the amount of cash in inventory.
SetGems
Input: integer
Sets the number of gems in inventory.
DebrisTest
Lets the player perform the 2.5D debris animation test.
ComboBallSummon
Summons a Combo Ball Spell.
MoneyObjectTest
Spawns a money object into the farm.
BangunSetAmmo
Input: BangunAmmo (0,500)
Sets the amount of ammo in the Bangun.
BangunSetLevel
Input: BangunLevel (0,5)
Sets the Bangun’s level.
BangunSetAll
Input: BangunAmmo (0,500), BangunLevel (0,5)
Sets the Bangun’s ammo amount and then the Bangun’s level.
ResetGlobalCriteria
Resets the progress on all net-total achievements such as MAX Catharsis and Explosive Rain.

A screenshot of a warning text exclusive only to Experiment Mode.
The new features available on Experiment Mode are exclusive only to the mode, and should not be saved to a normal farm file. The game does not prohibit players from doing so, yet are advised not to. All features may have been fully implemented in the Experiment Mode, but are yet to be fully implemented into the normal game.
The following features are exclusively available on Version 0.4.0's Experiment Mode:

The "True Clear" is meant to be achieved by reaching the maximum amount of everything in the farm. Currently it can only be achieved by executing the spacebar command TrueClear.

The piggybank is a little pig-shaped object that can temporarily store money for you. Money can be inserted into the piggybank by right-clicking on it. The money contained within it can be gained by destroying the piggybank without the use of Ball Bombs or Ball Mowers. When it is destroyed by manually clicking on it or shooting it with a Bangun, it will spawn money onto its location, which holds the exact amount of money it had been storing indefinitely. However, when it is destroyed by the explosion of a Ball Bomb, or by a Ball Mower's saws, it will not spawn any money and all the money stored within the piggybank is lost forever.

In version 0.4.0's Experiment Mode, you are unable to buy Banguns or Bangun Ammo. The player must use a speacebar command to get the Bangun and its ammo. Please do note
that the Bangun will be automatically discarded (reset to "level 0") if there is no Bangun ammo, rendering BangunSetLevel useless when executed before BangunSetAmmo.
Instead, it is recommended to use BangunSetAll to avoid unintentionally losing the Bangun. To enable Bangun mode, right-click to open the inventory menu and click on the Bangun option
which also shows the level of the Bangun. While in Bangun mode, you can execute spacebar commands and shoot by using the left mouse button and aiming with your mouse. The fire rate
depends on what the Bangun level is. The Bangun mode can be disabled by either right-clicking and selecting "Disable", or by pressing Escape.