S.E.X. Mode is a difficulty mode which introduces multiple new mechanics, limitations and its own special S.E.X. Skill Tree with 18 Skills.
The main mechanic of S.E.X. Mode are Mental Breaks. Mental Breaks are built up by being hurt in any way, after a being hurt a few times you will experience a random Mental Break out of 26 total Mental Breaks. These Mental Breaks have unique effects, most of which are negative with a very small number of them being overall positive.
S.E.X. Mode also introduces a level cap that limits your maximum achievable level. The level cap starts at Max LVL 15 and increases by 5-20 for each new boss (vanilla or calamity) killed, up to a Max LVL 155 (360 with calamity).
The S.E.X. Mode level cap can be disabled in the configuration menu.
Mental Breaks are unique effects, mostly negative, which occur when you've suffered enough Mental Break damage. Mental Break damage is increases every time you get hurt in any way.
There are a total of 26 different Mental Breaks which can occur once your Mental Break damage has reached its maximum. While some have positive effects, all of them have some kind of negative effect which can either be annoying or incredibly fatal.
The S.E.X. Skill Tree has many Skills that are related to Mental Breaks, like the entire Adrenal Boost branch and much more.
The duration of a Mental Break depends on the type of Mental Break, some might last a few seconds while other could last up to a couple minutes.
List of all Mental Breaks and their effects
Heartache "You're feeling a pain in your heart" - After a short period, a damaging heartbeat occurs which deals 25-50% of your maximum life as damage.
Controlless "You can't seem to control yourself" - Forcibly moves you in random directions every 0.33 seconds, this effect is enhanced while you're in the air.
Vertigo "You can't seem to focus your eyes" - Your screen starts moving in a square pattern around you which snaps back to your body after it ends.
Burnout "You're lacking energy to continue" - Gradually reduces your movement speed until you reach 15% of your maximum movement speed.
Schizophrenia "Phew, looks like nothing happened" - Many rainbow-colored projectiles and entities are spawned around you, spams many different chat messages and shows extra random damage numbers on hit or on heal to confuse you.
Breaksense "Great, you could do anything!" / "Awful, everything feels broken" - When above 75% life when it occurs, gain 10-25% increased most stats for the duration of the Mental Break. When below 75% life when it occurs, gain 20-45% decreased most stats for the duration of the Mental Break.
Paranoia "They're all out to get you" - Grants you the Dangersense effect, but increases the spawn-rate and spawn limit of enemies by 1000-3000% depending on the area.
Panic Attack "Complete panic has been unleashed" - Increases all your damage and critical hit chance by 5-15%, but take 5-10% of your maximum life as damage for every heartbeat that occurs.
Broken Psyche "None of this exists, what's the point" - The screen starts being filled with glitching squares, intentionally impacts your FPS and overall performance.
Dissociation "You're a stranger to your own self" - Your camera starts focusing on nearby enemies instead of you, the camera returns to your body if no enemies are nearby.
Heart Attack "Immeasurable pain is growing inside" - A long timer begins, once the timer runs out you take a massive amount of damage. Killing enemies increases the timer, but never removes it. Heartbeats indicate the current timer.
Fools Thought "You're ignorant to your innocence" - Slowly decreases your current EXP every few seconds, but will never decrease your level.
Magic Peril "A feeling of overwhelming magic?" - Converts all your damage types to magic, but whenever you're not at 100% mana you will lose 1-3 life every 3 ticks.
Irrational Choice "Your instincts are disoriented" - Activates a random ability from a different Class Skill Tree that you have chosen. The ability will be its weakest form without any Skill upgrades.
Nearby Anxiety "You can't shake this feeling" - Slowly drains your life whenever an enemy is nearby you, but gain 50% increased movement speed for the duration of the Mental Break.
Total Forgetfulness "Everything is weirdly confusing" - Completely overrides your controls for the duration of the Mental Break.
Hyper Adrenaline "The power of a God for a cost" - Grants you complete invincibility and 35% increased all damage for 8 seconds, but removes your invincibility and reduces all your damage and movement speed by 45% for the rest of the Mental Break duration.
Guilty Payback "Throw it all away, quickly now" - After hitting an enemy with an attack, throw a volley of copper coins towards the enemy. The coins deal damage based on your currently held weapon, but reduce your defense by 50% for the duration of the Mental Break.
Time Dilation "You can't keep up with anything" - Reduces your movement speed and the speed of your projectiles by 50% for the duration of the Mental Break.
Thorned Emperor "An emperor cut by their thorns" - Increases all your damage by 35%, but whenever you hurt an enemy by any means, take 2-8 damage yourself as well.
Faux Vampire "You've got a need for blood" - Constantly lose your life every tick (this cannot kill you by its own), but all your attacks gain life-steal equivalent to 10-20% of your attack damage.
Melee Peril "A feeling of berserking power?" - Converts all your damage types to melee, but grants you the Broken Armor de-buff for the duration of the Mental Break.
Karmic Justice "You get what you fucking deserve" - Grants you a variety of positive effects when you haven't started The Silence questline, but grants strong negative effects for every quest completed for The Silence.
Pacifistic Outlook "You want to create complete peace" - You can no use items or your weapons, but gain 4 seconds increased immunity time after being hurt, 15 increased life regeneration, 45 increased defense and 15% decreased movement speed for the duration of the Mental Break.
Pure Death "You've become Destroyer of Worlds" - Reduces your life regeneration to 0 and your current life to 1, but increases all your damage by 75% and your movement speed by 35%.
Lovers of Heart "You can't contain your own love" - Multiple lovers hearts burst out of your body, each costing 20 of your current life. These hearts have strong homing capabilities, attack enemies and heal you for 8-12% of the lovers hearts damage. Lovers Hearts damage is based on your progression (progress is tracked with boss kills). These hearts last for 8 seconds.
S.E.X. Skill Tree
The S.E.X. Skill Tree consists of 18 Skills which are mostly risk and reward oriented, granting you a positive and negative effect at the same time.
In order to completely unlock all Skills within the S.E.X. Skill Tree, you would at minimum need to be Level 39.
The Skill Tree also has an additional button underneath it which opens the Breakopedia of Mental Breaks.
List of all S.E.X. Skill Tree Skills and their effects
Stubborn Mind [Costs 2 Skill Points] - Doubles the amount of Mental Break damage needed for a Mental Break to occur, but your Mental Break damage slowly builds up when a boss is alive.
Critical Flaw [Costs 2 Skill Points] - Increases your EXP gained from most sources by 10%, but enemies gain a 5% chance of critically striking you for 1.5x of their damage.
Volatile Blood [Costs 2 Skill Points] - After being damaged for more than 15% of your maximum life, release a volley of volatile blood which damages enemies depending on your progression (progress is tracked with boss kills), but also increases the duration of all Mental Breaks by 10-25%.
Slowing Invincibility [Costs 2 Skill Points] - Increases your immunity frames after being hurt in any way by an additional 0.5 seconds, but getting hurt in any way slows your movement speed by 20% for 3 seconds.
Artificial Tank [Max Level 5] - Each level of Artificial Tank increases your maximum life by 10, but decreases your movement speed by 3%, up to 50 additional maximum life and 15% decreased movement speed.
Repressed Anger [Costs 2 Skill Points] - Increases all your damage by 15% while experiencing a Mental Break, but also increases the amount of Mental Break damage gained from getting hit by 25%.
Active Regeneration [Max Level 5] - Each level of Active Regeneration increases the chance for all your attacks to heal you for 5-15% of the attack damage by 2%, up to 10% chance for all your attacks to heal you.
Mindful Meditation - Your Mental Break damage starts slowly regressing after you haven't been hit for 10 seconds.
Relaxing Thoughts - Decreases the waiting time for your Mental Break damage to start regressing by half, down to 5 seconds.
Quiet Introspection [Max Level 3] - Each level of Quiet Introspection increases the speed of which your Mental Break damage regresses by 20%, up to 60% regression rate.
Impenetrable Mind - After an active Mental Break ends, gain immunity to Mental Break damage for 10 seconds afterwards.
Feel No Evil [Costs 2 Skill Points] - Increases the duration of Mental Break damage immunity by 3x, up to a maximum of 30 seconds of Mental Break damage immunity after an active Mental Break ends.
Touch No Evil - While you are immune to Mental Break damage, gain 25% increased movement speed.
Adrenal Boost 1 [Costs 2 Skill Points] - Whenever a Mental Break occurs, Adrenal Boost activates for the duration of the Mental Break. On activation, Adrenal Boost instantly heals you for 5% of your maximum life and reduces your defense by 33% for the duration of Adrenal Boost.
Adrenal Boost 2 [Costs 2 Skill Points] - Enhances the effects of the Adrenal Boost. It will now heal you for 10% of your maximum life and reduce you defense by 25%.
Adrenal Boost 3 [Costs 2 Skill Points] - Enhances the effects of the Adrenal Boost. You will also dodge the first attack that hits you when Adrenal Boost is active.
Adrenal Boost 4 [Costs 2 Skill Points] - Enhances the effects of the Adrenal Boost. It will now heal you for 15% of your maximum life and reduce you defense by 20%.
Adrenal Boost 5 [Costs 2 Skill Points] - Enhances the effects of the Adrenal Boost. It will now heal you for 20% of your maximum life and reduce you defense by 20%. Gain a 65% movement speed increase for 2 seconds once Adrenal Boost activates.