Epiphora

Effects

Tear delay gradually decreases as the player shoots in one direction. Accuracy also decreases as the fire rate increases.
- At max "charge", it will reduce tear delay by half, rounding down.
Rate of fire returns to its original value if Isaac stops firing, changes firing directions, uses an active item, or is hit.
- (Added in Afterbirth †) Being hit, changing rooms, and using items no longer reset the Epiphora bonus.
- (Added in Repentance) Entering an unexplored boss room will reset the Epiphora bonus.
  - During the delay when transitioning between rooms, picking up an item, or using an active item, it's possible to change the firing direction without resetting the bonus.

Epiphora technically works with items that require a charge (such as Monstro's Lung), but requires releasing the key or button, causing players to lose the effect.

Continuum: Reduces the need to change firing direction, allowing Isaac to maintain the increased rate of fire.
Dr. Fetus / Ipecac: Firing bombs continually will decrease tear delay, although doing so is not recommended since it increases the risk of self-damage.
(The Forgotten) The Forgotten: When tapping the attack button in a single direction repeatedly, the Ephiphora effect will cause the bone swings to speed up.
How to Jump: Changing firing direction while jumping does not reset the bonus, similar to when changing rooms.
Incubus: Incubus's fire rate will match Isaac's.
The Ludovico Technique: Fire rate increases while moving the tear in one direction; it has a negligible effect during normal gameplay.
Marked: Rate of fire only increases so long as the mark is continuously moved in one direction.
Rubber Cement: Reduces the need to change firing direction allowing Isaac to maintain the increased rate of fire.
(Added in Repentance) Rock Bottom: Isaac will never lose the benefits of Epiphora, even after he stops firing. This effectively makes Epiphora a substantial tears up. Fully charging Ephiphora is still needed to gain a higher tears stat if an item that would increase the tears stat is picked up.
Tractor Beam: Fire rate still increases when shooting in one direction, but will stay on the line (i.e. no loss in accuracy).
Loki's Horns / Mom's Eye: Allows for firing in multiple directions at once, decreasing need to change firing direction.

Brimstone: Effect only activates when holding charge in a specific direction, and deactivates when the charge is released, effectively making Epiphora useless unless Isaac has exceedingly high tear delay.
- (Added in Repentance) After charging an attack, continuing to hold the attack button will increase fire rate, but the fire rate is reverted when letting go of the attack button or changing the attack direction.
Chocolate Milk: Overrides Epiphora.
Epic Fetus: Overrides Epiphora.
(Lilith) Lilith: Lilith and her Incubus cannot gain extra fire rate from Epiphora.
- (Added in Repentance) Incubus' fire rate will increase without the accuracy penalty
Mom's Knife: Overrides Epiphora.
Monstro's Lung: Overrides Epiphora.
(Tainted Isaac) Tainted Isaac: If you pick up an item and drop Epiphora while holding the attack button you will keep the fire rate. The effect will disappear upon entering a new floor.
Tech X: Overrides Epiphora.