All difficulty modes are changed in the mod config menu ('Screw' button at bottom right corner of screen when selecting this mod)
There are 3 base difficulty modes: Normal, Expert and Master mode.

In Normal mode, HP of the boss is set to 2800.
The boss now has 2 phases.
In its 1st phase, the boss will attempt to charge at the player 3 times, and follow up by spawning 2-3 minions.
Once below 50% HP, The boss will be in its 2nd phase.
In this phase, the boss will charge at the player 3 times at a faster speed.
Damage of the boss is set to 54 and 80 in Phase 1 and 2 respectively.
HP of the minions is set to 8, and its damage is set to 22.5

In Expert and Master mode, HP of the boss is set to 3640 and 4641 respectively.
The boss now has way less taunt animations and charges faster in all phases.
Additionally, The boss now has 3 phases.
In its 1st phase, the boss will attempt to charge at the player 3 times, and follow up by spawning 3-4 minions.
Once below 65% HP, The boss will be in its 2nd phase, at which it will spawn 9-10 more final minions.
In this phase, the boss will charge at faster speeds.
It has 4 sub-phases during phase 2 to which it changes at 50%, 40%, and 25% HP respectively.
During sub-phase 1 it does 3 normal dashes.
During sub-phase 2 it does 3 normal dashes and then 2-4 rapid chain dashes.
During sub-phase 3 it does 5 rapid chain dashes.
During sub-phase 4 it does 4-6 rapid chain dashes.
Once below 4% HP, the boss reaches its 3rd phase, in which it will start performing rapid chain dashes until either it dies, or its target dies.
Expert and Master mode exclusive drops have also been introduced.
For Expert mode, Damage of the boss is set to 105 and 130 in Phase 1 and 2 respectively.
Damage of chain dash is set to 170.
HP of the minions is set to 12, and its damage is set to 43.5.
For Master mode, Damage of the boss is set to 170 and 250 in Phase 1 and 2 respectively.
Damage of chain dash is set to 300.
HP of the minions is set to 15, and its damage is set to 45.
The minions also no longer have taunt animations in Expert and Master mode, and no longer panic when set on fire.
The boss has less cooldowns than Normal mode on Expert and Master mode.

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In addition to the 3 base difficulty modes, there are 3 sub-difficulty modes: Journey, For The Worthy and Armageddon.
In these sub-difficulty modes, the boss and its minions will inherit characteristics from the base difficulty modes.

In Journey mode, the boss has an additional 25% HP on top of the base difficulty modes.
The minions will have 30% additional HP on top of the base difficulty modes.
High value rewards will be given for defeating the boss in Journey mode.

In For The Worthy mode, both the boss and the minions are immune to all forms of Crowd Control, and deal significantly more damage.
Additionally, the minions no longer have an attack cooldown.
The boss also has a movement boost modifier to its charges on top of the base difficulty modes, and has less cooldowns on top of the base difficulty modes.
The boss will always spawn 5 minions in the 1st phase.
The boss and the minions have 2800 and 8 more HP respectively on top of the base difficulty modes.
Multiple exclusive rewards are introduced for this difficulty mode.

In Armageddon mode, the boss and its minions now will 1-shot any character not in god-mode.
This difficulty mode was introduced for players who want to try no-hit the boss.
Multiple high value rewards will be given for defeating the boss in Armageddon mode.