Mechanics

Rally Effect

 * When you take damage, a mechanic called the Rally Effect activates. This lets you repair some of the damage by dealing damage to enemies.
 * Upon taking damage, the lost portion of the health bar turns from green to orange, indicating how much health can be regained by dealing damage.
 * This orange portion begins to shrink after an 0.08-second delay, at a rate of 30% maximum health per second until it disappears, leaving only the green portion and indicating the Rally Effect has ended. If the player takes damage again while an orange portion of the bar remains, the bar will be discarded completely for a new orange bar based on the new health loss, resetting the Rally Effect.
 * The Recovery Mutation causes Rally health to drain at 0.16 seconds (usually 0.08) after taking damage, at a rate of 15% of maximum health per second.
 * While an orange portion of the health bar remains, damaging enemies heals the player for 12% of the damage inflicted, with each hit's recovery capped at 20% of the original health lost.
 * Total Rally health recovery is reduced by 65% while the player is protected by a force field, such as the one given from taking hits with a Shield equipped.
 * Since v1.9, the Update of Plenty, rally is no longer affected by skills. This means they cannot gain health back.

Sudden Death Prevention

 * If the player takes a hit that would normally kill them while their health is above 25% of maximum health, that hit instead reduce health to 1 and all nearby enemies will be stunned for ≈1 second.
 * Sudden Death Prevention normally takes 45 seconds to recharge before it can activate again, but its cooldown can also be reset by drinking a potion or refilling your health completely in any way.

Breach

 * If the player significantly damages an enemy while they are in the middle of an attack or defensive maneuver, the overwhelming force may breach that enemy's defenses, interrupting the maneuver and stunning them for 1.4 seconds.

Basic Breach Mechanics

 * By default, damage dealt to enemies by direct hits (not damage-over-time effects) is added to an enemy's breach damage.
 * Breach damage, at an enemy tier of 1, decays at a rate of 20 points/second until it reaches 0.
 * Breach damage must exceed 100 to cause a breach.
 * Breach damage's decay rate and the required breach damage to cause a breach both scale with enemy tier using the same formula that increments enemy health.

Breach Resistance

 * Enemies can be more resistant or more vulnerable to breach during certain maneuvers. The degree of resistance or vulnerability is quantified by the maneuver's breach resistance as follows:
 * If a maneuver's breach resistance is equal to 0, breach damage accumulates normally as the enemy takes damage during the maneuver.
 * If a maneuver's breach resistance is positive (greater than 0), damage taken by the enemy during the maneuver is reduced by (breach resistance x 100)% for the purposes of breach damage accumulation (e.g. if a maneuver has a breach resistance of 0.5, a 40-damage attack would only increase breach damage by 20 points).
 * If a maneuver's breach resistance is equal to 1, the enemy cannot be breached at all during the maneuver due to damage taken being reduced to 0 for the purposes of breach damage accumulation.
 * If a maneuver's breach resistance is negative (less than 0), damage taken by the enemy during the maneuver is increased by (-(breach resistance) x 100)% for the purposes of breach damage accumulation (e.g. if a maneuver has a breach resistance of -1.5, a 40-damage attack would increase breach damage by 100 points, enough to cause a breach to occur if the enemy has an enemy tier of 1).
 * In general, larger enemies are harder to breach than smaller enemies, melee attacks have higher breach resistance than ranged attacks, and Bosses and their minions are immune to being breached.

Breach Bonus

 * Some of the attacks from the player's Weapons are more or less effective at causing breach damage on all enemies. The degree of effectiveness of breach damage generation for a particular attack is quantified by its breach bonus as follows :
 * If an attack's breach bonus is equal to 0, breach damage is equal to attack damage.
 * Damage from Shields and non-Weapon sources can be assumed to have a breach bonus of 0.
 * If an attack's breach bonus is positive (greater than 0), breach damage is increased by (breach bonus x 100)% compared to breach damage for a breach bonus of 0 (e.g. if an attack with a breach bonus of 1 deals 40 damage, that attack increases breach damage by 80).
 * If an attack's breach bonus is negative (less than 0), breach damage is decreased by (-(breach bonus) x 100)% compared to breach damage for a breach bonus of 0 (e.g. if an attack with a breach bonus of -0.5 deals 40 damage, that attack increases breach damage by only 20).
 * If an attack's breach bonus is equal to -1, the attack cannot cause a breach to occur due to damage being reduced to 0 for the purposes of breach damage generation.

In general, breach bonus is higher for melee attacks than for ranged attacks, greater for final blows of weapon combos than for first blows, and larger for slow weapons than for quick weapons.

Note: The bullet points for breach bonus effects assumed that attacks were occurring during enemy maneuvers with a breach resistance of 0. For cases in which breach bonus and breach resistance are both non-zero, final breach damage is obtained by applying the attack's breach bonus effect first, then the enemy maneuver's breach resistance effect.

Dive Attack

 * By pressing the jump and down buttons at the same time, a dive attack is performed. This attack negates the stun from falling long distances and deals damage to enemies. Stun still happens if the dive is long enough (like the exit elevator in Ramparts).
 * 3 levels of damage can be dealt with the dive attack.
 * If the distance fallen is at most that achieved by double-jumping from a flat region with no platforms or ledges nearby, the player deals 35 base damage in a 1-tile radius (60 base damage in a 2-tile radius if the player possesses the Ram Rune).
 * If the distance fallen is more than double-jump height, the player deals 90 base damage in a 2-tile radius (110 base damage in a 4-tile radius if the player possesses the Ram Rune).
 * If the distance fallen is more than 2.5 stories, dive attack damage is increased by a further 50%, producing final base damage values of 135 without the Ram Rune, and 165 with the Ram Rune.
 * Dive attack damage scales based on the highest of the player's stats.
 * The dive attack is counted as a melee attack, and so it can trigger a variety mutations such as Melee and Rampager, as well as Heart of Ice. However, for obvious reasons, Thorny will not damage the player, even if struck from behind.

Force Field
See the Status Effects article for more information about this effect and other ones like this.
 * Force field is an effect that can be applied by certain weapons, and can be applied to enemies as well. Force field provides total invincibility for the player and enemies.

Curse
See the main article for information about Curses.
 * Curse can be attained from:
 * Opening a cursed chest.
 * Breaking a golden door.
 * Having the Cursed Sword in your inventory.
 * Eating food whilst possessing the Acceptance mutation.
 * Picking up a Corrupted Artifact
 * Being cursed makes you die instantly from most forms of damage.
 * Curse death won't be triggered by:
 * Darkness damage.
 * Malaise damage.
 * Curses stack.
 * The Homunculus rune does not function if you are cursed by anything other than the Cursed Sword.
 * Curse is reduced by killing enemies, save for the Cursed Sword's exception, which is lifted by dropping this weapon. It also DOES NOT stack with all other sources.
 * Alienation increases the counter by 50%, while Acceptance reduces that by 50%. As mutations can only be taken once per each transition area, the newer taken mutation will scale it's effects on the previous one's value, with the terminal value rounded up. For example, if the player gets a 10-kill curse, then alienation, they will raise the counter to 15. If they get acceptance later on, it will decrease the counter by 7.5. However, as curse values can't be decimals, the player will end up with a 8-kill curse.

Enemy Teleportation

 * Starting from 4 BSC, almost every enemy gets the ability to chase after you via teleporting, akin to Elites and worms. Unlike Elites and worms, you'll see a brief red silhouette accompanied with red circle indicating where they will teleport and which direction they will face (though sometimes they face the opposite direction).
 * Enemies lose this ability if they're shielded.

Accelerated Movement
See the Status Effects article for more information about this effect and other ones like this.
 * By killing 5 enemies in a short amount of time, your movement speed is buffed for 10 seconds (30 seconds with the Velocity Mutation), boosting running speed by 40%, rolling speed by 12%, and climbing speed by 50%. Killing an enemy while affected by this buff refreshes its duration.

Falling

 * Unless you fall off of a building in The Ramparts or into the abyss in Astrolab or Cavern (in which case you take 30 base damage, scaled by the monster level of the zone), there is no fall damage in Dead Cells.
 * However, if you fall from a long enough distance, you will be temporarily stunned.
 * The stun duration increases with the distance the player has fallen.
 * Enemies, however, can get hurt and killed from a fall.
 * In addition, if a falling enemy happens to land on top of another enemy, they will both take damage.
 * This distance is much shorter than the distance that will cause the player to be stunned, so using something that causes knockback such as the Assault Shield or the Spartan Sandals to take advantage of this is a good idea. In fact, Spartan Sandals will always cause the enemy to take minimum fall damage regardless of the distance.
 * Dive attacks prevent the stun caused by falling. However, there is also a limit of how much the dive attack can prevent this stun. Really high heights, such as one found in some safe areas past The Collector, can still cause a falling stun even if the player dive attacks. Rolling in mid air will reset the dive, allowing you to dive again during very long falls.

Parry

 * Shields can parry attacks, nullifying their damage entirely rather than merely reducing it, and briefly stunning the attacker. Parries can also reflect most projectiles. More information on parrying is given on the Shields page.

Backpack

 * When the player obtains a weapon which uses both of their weapon slots, or a two-slot weapon, they will gain access to the backpack slot. This slot can carry one primary single-slot weapon, but it cannot be used until the player picks up another one-slot weapon and replaces their two-slot weapon.

Status Effects
See the main article for information about status effects.
 * There are 9 main status effects: Stun, Root, Freeze , Slow , Burn , Poison , Bleed , Shock , and Oil.
 * They either prevent enemy action (Stun, Root, Freeze , Slow ), or deal damage over time ( Burn , Poison , Bleed , Shock ). Oil is the only one that does not directly affect enemies, and instead boosts the damage of Fire.
 * Additionally, the Frostbite mutation will transform Slow into a pseudo ‘damage over time’ effect.
 * Weapons and Skills can have modifiers that increase damage dealt to an enemy suffering from a specific status effect.
 * There are multiple other effects present in the game, such as temporary damage reduction, that either the player or enemies can receive. The results of these effects can vary and are often only inflicted by specific items or mutations.

Environmental Effects
The environment in Dead Cells can affect the player and enemies in many ways.

Liquid interactions

 * Enemies in pools of liquid are immune to burning effects, unless covered in inflammable oil.
 * Enemies that take damage from ice-element attacks while standing in a pool of liquid cause the pool to chill dramatically, causing all other enemies in the pool to be slowed as if they had recently thawed after being frozen, as well as being rooted in place.
 * Enemies that take damage from electric-element attacks while standing in a pool of liquid cause the pool to become electrified, dealing 18 base Shock DPS to all enemies in the pool for 2 seconds. Shock DPS scales with the scaling stat of the item producing the attack that electrified the pool. Electric weapons deal critical damage to enemies in water.

Poisonous puddles in the Toxic Sewers and Ancient Sewers

 * In the Toxic Sewers as well as the Ancient Sewers, the player will come across pools of poisonous water, which will deal damage, should they be entered. Enemies will not take damage from these pools.
 * When in contact with the poison, the player starts taking damage equal 10 damage in 2 seconds, divided into 5 ticks per second, each dealing 1 damage.
 * The damage is a damage-over-time effect that refreshes every 2 seconds, should the player still be standing in the poison.
 * It is possible to avoid taking damage, as the contact is only registered if the player touches the ground of the puddle, so if he runs over a 1-tile broad puddle or avoids contact with the second part of the double jump, which allows him to touch the liquid but not the ground, he will not take any damage.

Forgotten Sepulcher's Darkness

 * In the Forgotten Sepulcher, the darkness of the area is a threat to the health of the player.
 * Without stepping into a light source for 12 seconds, the player will start taking damage.
 * Killing enemies reduces the darkness a tiny bit.
 * The damage is dealt in ticks, with 3 ticks per second. The damage per tick quickly increases and can be lethal if the player doesn't find a light source in time.
 * Entering a lit area resets the 12 second timer as well as the tick damage.
 * Damage from the Darkness will not instantly kill players who are cursed or are carrying the Cursed Sword.
 * The darkness mechanic can be enabled in custom mode for ALL biomes.

Malaise
See the main article for information about the Malaise.
 * Taking damage from Key Elites in High Peak Castle causes infection.
 * Key Elites' hits give you 2 points of infection.
 * The maximum level of infection is 10.
 * After reaching the maximum infection level, the player's current HP is capped at 10% with no way of healing above this threshold. Heal related mutations, such as Necromancy will be ineffective unless the infection level is reduced.
 * Drinking a flask charge will reduce the infection level by 5.
 * Eating food will reduce the infection level by 1.
 * This effect will occur from every enemy if 4 BSC are active, where every enemy, except for ones spawned from other enemies, can inflict it.
 * Food can also be infected, which will increase the infection level by 1.