Leveling Overview

Nuclear Throne follows a simple leveling system. Radiation that drops from enemies serves as experience points which will fill the rad meter. Once filled the character will level up, and upon leveling up they may pick one skill/upgrade usually from a pool of four known as mutations.

The player will always start at level 1 at the start of the run, and every consecutive level up will grant a mutation up to level 9. This means that a typical run will have 8 mutations, but a 9th can be gained through Crown of Destiny.

Reaching level 10 is referred to as level "Ultra". It gives choices between mutations that are specific for each character, and will typically give a boost to a character's unique active or passive ability. Any additional rads beyond this point will fill the ultra meter which are used as additional ammunition for ultra weapons. Rads gained with a full ultra meter will be wasted similar to getting pickups with full health/ammo.

The following table lists how many rads it takes to obtain each level as well as the total rads collected at that point.

Every level up gives a set of four mutations (five with Horror) in which the player can select one, from a total pool of 28 mutations normally. Once a mutation is selected it is permanently removed from the pool for that run. The exception to this is Last Wish which is re-added to the pool upon consumption.

In a vanilla run every set can be considered completely random as each mutation has equal chances of reappearing. In reality each mutation set is seeded, just that this seed is unknown to the player. There are two exceptions to this however, the first being weeklies which can be replayed any number of times within the week. Daily challenges may only be played once but is also a shared set seed to each player meaning they can share information from their own runs to the benefit of other.

Leveling Mechanics

There is a full page of in-depth mechanics for the Daily Sheet. This section serves more as the basic introduction, and any leveling mechanics that can apply to a normal run.

The example image illustrates basic leveling in the game. Any time the player levels up they advance the set number from one, starting from Set 1. On Betas they start from Set 0, though the starting set is only relevant to dailies/weeklies.

The player only sees the first four mutations in a set while Horror sees the 5th mutation slot as well. If a mutation is taken then it gets removed from the mutation pool, so if the player takes Sharp Teeth in Set 1 then it will be removed from the pool in Set 2, and they will see Thronebutt instead as the 4th slot mutation. This can easily be practiced on the Weeklies by playing it multiple times and trying different mutation sets in each run.

Taking Patience or consuming Last Wish on Non-Beta will advance the set number by one similar to leveling up. On the Betas they are a 'fixed' randomly seeded set regardless of when the reroll mutations were taken. These are essentially random on a normal run but can effect daily/weekly sets.

Bug: On Non-Beta only if two or more sets are seen and Patience is taken before the last set is seen, then a set is skipped and the last set seen will show up twice, the second time being once Patience is granted after the next level is completed. While the mutations given cannot be predicted on a normal run this can situationally be abused for a daily or weekly run if the sets are already known.