Mutations

Mutations, introduced in the Foundry Update, are passive modifiers which replace Stat-based secondary effects from the Brutal Update. They can be obtained between levels from Guillain.

Most mutations are not available initially - to unlock them for future selection, one must first bring their blueprints to the Collector, then spend the requisite amounts of cells.

Mechanics
The player can only benefit from a certain number of mutations at once. Each area cleared in a run allows the player to use one more mutation up to a hard limit of 3 mutations. However, the player can choose to spend gold between levels (cost starts at 2500 and greatly increases after each reroll, up to 50000) to remove all current mutations, allowing for a new set of mutations to be chosen to replace the old set.

Most mutations are associated with a specific stat (Brutality, Tactics or Survival), scaling their benefits based on their current levels. Specifically, base damage and healing magnitudes for these mutations are multiplied by (1.15^(n-1)), where n is the current level of the appropriate stat, and rounded to produce the final effect magnitudes (e.g. if a Brutality-scaling mutation provides 90 base extra DPS and the player's Brutality level is at 2, the final extra DPS is (90 × (1.15^(2-1))) = 90 × 1.15 = 103.5 ≈ 104). Note that damage and DPS bonuses on attacks from mutations are not affected by gear-specific damage bonuses or Affixes.

General mutations, however, have fixed benefits which are not affected by the player's stat levels, except for Instinct of the Master of Arms mutation.

Removed Mutations
These mutations were removed from the game in v1.1 (December 2018/Jaunary 2019). Efficiency's/Fireworks Technician's scaling with Tactics/Brutality is given in the following table: