Galaxies

Galaxies are modifications of the game that, when completed, are created. Each Galaxy gives certain benefits, and can be created multiple times (not fractionally) to amplify those benefits. Each unique Galaxy has a restriction, goal and reward. The restriction is what is changed in the game, usually making it harder to progress. The goal is the requirement to create that galaxy, which scales with the amount owned.

Galaxies are numbered as roman numerals.

List of unique Galaxies
Note that the goals for all of the Galaxies are identical to the requirement to gain a Star, which is determined by this code: ...years per second, where   is the amount of that Galaxy already created.

Galaxy I
"The temporal and nucleosynthesis effects of space energy is disabled, and gain 1e50x less spacetime"This is the 1st Galaxy in, and likely among the easiest of them all to create.

Rewards
Gain $$x$$ free applications of Nucleosynthesis Upgrade #2, where $$x$$ is equal to the completions of this Galaxy.

Galaxy II
"Only your star types increase the compressor's effect with a squared effect. Space Energy no longer boosts Space Foam. Normal Energy is disabled. Cap Time Compressors to 21"This is the 2nd Galaxy in.

Rewards
Raise the Stellar effect to the $$2-\frac{1}{x+1}$$, where $$x$$ is the amount of this Galaxy created.

Galaxy III
"You can't gain any Space Energy nor Normal Energy, and their effects are disabled. Cap Time Compressors to 19, but double their overall speed"This is the 3rd Galaxy in.

Rewards
Increase the Space Energy exponent gain by +$$\frac{x}{100}$$, where $$x$$ is the amount of this Galaxy created.

Galaxy IV
"Your space foam is capped to your normal energy, Time Compressors are 10x as expensive and capped to 18, but the second Supernova upgrade works"This is the 4th Galaxy in.

Rewards
Increase the base of the third Supernova by the amount of this Galaxy created.

Trivia

 * This feature is basically Challenges in regular incremental games, except that they can be 'completed' multiple times.