v.2.2.
Few more clean ups.

v. 2.1.
Some little fixes

v.2.0.
Mod now makes use of REPENTOGON, for some better synergies.
Mod still works without it, but mostly works same as v.1.11, in that case.
p.s.: by familiars, I only mean familiars, that copy player's attacks, e.g. Incubus.

General (Rep/Rgon)
⠀•⠀Mod Config Menu is now supported.
⠀•⠀Now corresponding damage multiplier is used for familiars.
⠀•⠀Familiars have their own Neptunus charge instead of totally depending on player.
⠀•⠀Only Incubus and Umbilical baby show their Neptunus charge.
⠀•⠀New Brimstone synergy. Was changed to fit concept art[bindingofisaacrebirth.fandom.com], but I also remember somebody suggesting it somewhere.
⠀•⠀Reworked Mom's Knife synergy.
⠀•⠀Little changes to Mom's Knife + Ludovico synergy.
⠀•⠀New Spirit Sword synergy.
⠀•⠀Little changes to Epic Fetus synergy.
⠀•⠀Calculated new charge/discharge formula, based on vanilla Neptunus values.

The Ludovico Technique:
(Rep/Rgon) same as before.

Monstro's Lung:
(Rep/Rgon) Neptunus tears aren't fired, unless Lung is charged.

Technology:
(Rep/Rgon) now is little closer to vanilla Neptunus.
(Rgon) +Chocolate Milk: now works like vanilla Neptunus + Chocolate Milk combo.
(Rgon) Shortening delay between shots now works for familiars.

Tech X:
(Rgon) item's charge is shortened, depending on Neptunus charge; while Neptunus charge > 5%, shoots automatically, when item reaches max charge.
(Rep) same as before: laser is widened, depending on charge.

Brimstone:
(Rep/Rgon) beam's duration is increased up to 5x (40 ticks, normally);
(Rep/Rgon) +C Section: more fetuses are spawned due to longer duration.
(Rep/Rgon) +Soy/Almond Milk, Ludovico: now also increases damage, additionally to width (as increasing duration would not be helpful).

Dr. Fetus:
(Rep/Rgon) now is little closer to vanilla Neptunus.
(Rgon) Shortening delay between shots now works for familiars.

Epic Fetus:
(Rep/Rgon) trajectory of spawned tears is now different (tears now fly pretty high up, instead of just moving horizontally). Number of tears spawned depends on Neptunus charge.

Mom's Knife:
(Rep/Rgon) depending on Neptunus charge, 0 to 3 pseudo-knives (in reality tears with changed visuals) are launched for each knife.
(Rep/Rgon) +Ludovico: now whirlpool is spawned only for main/central knife, but it's size and pulling force also depends on number of knives.

Spirit Sword:
(Rep/Rgon) usual attack is transformed into spin attack, requiring some Neptunus charge.
After transformed Spin Attack, you can continue charging to activate normal spin attack.
Note that transformation isn't perfect: transformed spin doesn't reflect enemies' projectiles and it's hitbox is smaller than it seems to be.

Forgotten's Bone/Berserk:
(Rep/Rgon) little misc. changes and fixes.
(Rep/Rgon) +Cursed Eye: should work more consistently.
(Rep/Rgon) +Monstro's Lung: cancels tear shoot, only adding additional lung-style tears (bones due to character).
(Rgon) +Brimstone: cancels tear shoot; Brim-ball's velocity is now increased depending on Neptunus charge.
(Rep/Rgon) +Epic Fetus: works now, similarly to normal Epic Fetus.

C Section:
(Rgon) item's charge is shortened, depending on Neptunus charge; works pretty like vanilla Neptunus.
(Rep) same as before: fetuses shoot tears, no dependance on Neptunus charge.
[/list]


(Rgon) now normal Neptunus works for T. Lilith.
(Rgon) Now ALL synergies work same for familiars;

v.1.11.

• Fixed Neptunus + chargeable Technology (Tech + Monstro's Lung, Tech + Chocolate Milk, Tech + Cursed Eye) not working.
  
• Fixed Neptunus + Dr. Fetus and Neptunus + Technology may being broken in case of gaining tears up.
  
• Neptunus + Spirit Sword now charges way faster (2x as fast in particular), to make waiting for Neptunus effect more desirable than just spamming it as usual.
  To balance such change, size increase was lowered (1.25x -> 1.2x).
  
• Chargebar now is only rendered above water. No more confusing (and a bit broken) reflection!
  
• Changed handling of extra sprite for Neptunus + Spirit Sword. Now it uses just sprite instead of entity with changed anm (in particular, it was mist effect).
  Though, such trick is still used for Neptunus + Mom's Knife + Ludovico Technique whirlpool effect, as there is no way to render that normally with just sprite, without entity.
  
• Removed outlines for droplets from lasers' impacts. That way it's less distracting and also closer to the appearance of creeps from Aquarius, Holy Water and such.
  
• Mod now recolors Haemolacria (and Haemolacria + Brimstone) tears to blue if you have Neptunus.
  This change is pretty imperfect as it will result in different color of child tears/lasers. But due to how game works this is the best option, I guess?..

Yeah, in case you didn't know (and I'm pretty sure you didn't notice this detail), if player has Neptunus, mod changes tears from their blood variants back to respective blue/normal ones. Feature was in the mod from the very beginning - from v.1.0. It's just that I didn't consider it that necessary to give it some attention.


Also, sorry for this little rant below, I just had some "Edmund, you little f" energy that I had to let out.
Seriously, I don't even have that many mods, yet it's already second time when I run into the same problem - effects related to tears have nil set as their spawner. Why on earth it works like this, Edmund!? There can be more than 1 player, and I NEED to know, which one of them created this goddamn poof! Or even better, that poof may be created by some enemy's bullet! And that isn't some sort of "special exclusive" for poofs! Haemolacria trails also have nothing instead of spawner. WHY? Unlike poofs, which sort of suggest, that there is no tear already, trails are created while tear still EXISTS! I don't wanna guess, which player is possibly responsible for some effect from a tear, I want to know it for sure! At this rate I will have to create mod that will remove all "natural" tear effects and will spawn them manually with player set as their spawner!

v.1.10.

• Fixed SoyBrim.

Yeah, that's all.

Thanks @Laird Ichofox, for reporting this.

Back to normal.

Oops. Uploaded wrong mod.

v.1.9.
⠀•⠀Fixed Dr. Fetus and Epic Fetus causing errors.
⠀•⠀Made more meticulous check before applying effects for tears and lasers.
On one hand that decreased number of synergies, on other made things more stable.
E.g., having Neptunus+Spirit Sword+Ludovico with "More Spirit Sword Synergies" mod by JamesB456 previously lead to bug, and could even crash game.
Another example - brimstone lasers from Dr. Fetus Brim-Bombs, also gained effect, and were being widened.

v.1.8.
Mostly, just little fixes.

• Fixed error reported by rainy (oversight at knife update, that lead to error).
  
• Ludovico tears spawned by incubus and alike familiars now work.
  
• Fixed brim lasers not being widened if character couldn't shoot (e.g. Lilith + Brim).
  
• Tears created by Neptunus+Monstro's Lung and Neptunus+Monstro's Lung+Bone/Berserk now inherit velocity from player's movement.
  Familiars now have lower dmg multiplier in these synergies (0.8~1.3 --> 0.6~1)
  
• Fixed Monstro's Lung + Bone/Berserk causing error if character couldn't shoot or if it was T. Lilith.

v.1.7.

• Made special chargebar, instead of recoloring default one. Compatible with Improved Chargebars mod.
  
• Improved sword synergy visual. Now, under physical neptunus sword, you'll see a water made one.
  While physical will have size of normal sword, water one will have size of an actual attack (making much easier to see how much attack is largened). It's also custom sword compatible now.
  
• Yet another Forgotten/Berserk change. Now, instead of spawning multiple tears, huge water splash will be spawned.
  Splash's size and damage depends on Neptunus charge.
  Splash will gain some of tear effects, such as inflicting poison or burning.
  
• Remade Knife+Ludo+Neptunus synergy so it doesn't feel awkward. Now it will spawn whirlpool, which will pull enemies and pickups.
  Whirlpool's size, and pull force depend on Neptunus charge.

Mod is taking it's final shape more or less.