Initially, it's possible to attack a planet only once you have enough bacteria to destroy 100% of the population. Starting from Planet 6, you can attack an unlimited number of times until it is finally destroyed.

A planet counts as destroyed if its remaining population has been reduced to 0. However, it's not possible to attack a planet if the player cannot destroy enough population to gain even 1 Gene Strand.

The amount of population that is destroyed during the attack is equal to the total of the population destroyed by Bacteria and Nanobots.

Using Bacteria

The formula that determines the percentage of population that will be destroyed by Bacteria is based on the SIR model for the spread of infectious diseases.

For this reason, it can sometimes take more Bacteria to kill the last 1% of the population that it was required to destroy the first 99%.

The total number of Bacteria required to destroy 100% of the initial population is calculated according to the following formula:

BacteriaNeeded = Population × 9.9 × 15ShieldLevel

Using Nanobots

The percentage of population destroyed by Nanobots is calculated according to the formula

where

• Population Destroyed - how many percent of the initial planet population will be destroyed by Nanobots in the current attack. This is limited to 40% of the initial population, so it's impossible to completely destroy a planet only with Nanobots in the first attack.
• Nanobot Count - the current number of Nanobots owned by the player.
• Nanobot Resistance Coefficient - a number that is determined by the Nanobot resistance of the current planet.
• Nanobot Strength - a multiplier that is set at 1 by default and is multiplied by any increases to Nanobot strength, such as Planetary Research discoveries and Dark Matter Institute technologies.

Rewards

Killing a percentage of a planet's population earns Gene Strands.

If the player has already unlocked Minerals, completely destroying a planet also has a chance to drop a Mineral native to the current planet.

Destroying planets also unlocks new game mechanics and upgrades.

Reset

Both attacking and destroying planets resets certain resources, upgrades, and bonuses.

Attacking a planet resets:

• Bacteria
• Bacteria Colonies
• Bacteria Upgrades
• Nanobots (if the planet was not destroyed)

Attacking a planet does not reset:

• Gene Strands
• Gene Strand Upgrades
• Evolved Bacteria
• Bonuses from Planetary Research
• Achievements
• Diamonds
• Scientists
• Dark Matter

Destroying a planet resets:

• Bonuses from Planetary Research

Destroying a planet does not reset:

• Nanobots that were not necessary to destroy the planet

Each planet has a larger population than the previous one. Population can reach large numbers in early game, which are displayed using abbreviations or scientific notification, if it has been enabled in the settings menu. The higher the population, the more Gene Strands can be earned from completely destroying the planet.

Even though planet population is not technically a form of defense, planets with higher population are harder to destroy, because they require additional Bacteria to infect.

It's possible to view the population of previous planets since the last Black Hole in the Destroyed Planets panel.

Currently, there are two types of planet defenses: Nanobot resistance and antibacterial shields.

Nanobot Resistance

Nanobot resistance reduces the effectiveness of Nanobots.

Nanobot resistance coefficient is determined by Nanobot resistance and it is used to calculate the effectiveness of Nanobots when attacking the planet.

Shields

Starting with Tesmielara (Planet 20), all planets have shields, which makes them harder to destroy.

The shield level increases by 1 for each planet. So the next planet after Tesmielara will have Level 2 shields and so on.

Shields multiply the amount of Bacteria needed to destroy the planet by 15x, where x is the shield level.

Early Game Planets (1-34)

Late Game Planets (34+)

There is no limit to the number of planets, but as of version 1.2.1 Minerals can be found only up to Planet 67 (Tapluatos)