Up-B: Growth (Spawns a ladder, by agreement)
Side-B: Move (Much smaller than the AT; sad we couldn't put it in neutral position for Kirby)
Neutral-B: Venus Psyenergy (uses psyenergy that acts differently in the air and on the ground)
On Ground: Spires (charges up and creates spires of earth to either side, more spires and bigger ones grow as it's charged like the higher level spells)
In Air: Rock Fall (similarly chargable, though less sizable, instead creates rocks that fall fron under Isaac, possibly at an angle?)
[I find it humorous now that I've look through the game again that these both go the opposite direction in their animation, but we (understandably) thought spires erupted from the ground and rock fall had the rocks falling downwards]
And then we have the gimmick of the set.
Down-B: Summon
When you use certain moves (particularly smashes and such) you'll use Djinn, which will then be unusable making the attack weaker, and plain reducing your stats while they're unset. If you use Djinn in order within their same element then you can summon the better summons, but using a different element resets them.
Djinn:
Flint: Sweetspot does great knockback (used in Side Smash or Down-Air)
Granite: Gives Isaac Super Armour for a few seconds (used in Power Shield)
Sap: Sweetspot drains a little HP (used in last hit of Jab combo)
Bane: Poisons the enemy (used in Down-Tilt)
[Venus Djinn increase weight and launch power, which decrease when used]
Forge: Increases all attack damage for a few seconds; more increase than Djinn decrease (Used in Up-Tilt)
Scorch: Creates an explosion is sweet spotted widening range further (Used in Down Smash)
Cannon: Hitting head on coats Isaac in flame (used on Dash Attack)
[Mars Djinn increase your damage output, which decreases when used]
Gust: If sweet spot lands it will combo into a triggered second attack (Used in Neutral/Forward/Back Air)
Smog: Surrounds the target in smoke, less than smoke grenade mind (Used in Forward Tilt)
Zephyr: If timed right after mid-air jump you can trigger a second mid-air jump (Used in triple jump)
[Jupiter Djinn increase speed and jump, which decrease when used]
Sleet: Freezes target when sweet spotted (Used in Up Smash)
Spritz?: Creates a spray of water that pushes target towards top of the screen (Used in Up-Air)
Fizz: Heals the user a little (Unsure, used in either Taunt or extended idle animation)
[Mercury Djinn increase defense, decreases when used)
Summons:
Venus: An explosion from the ground with solid upwards knock back.
Ramses: Ramses slams his fists into the ground burrying anyone underneath.
Cybele: Creates vines that will grab anyone in it's way, trapping them and deals continuous damage for a while.
Judgement: Massive movable laser from the sky, hardest to pull off, but very powerful.
Mars: A large explosion with a good area of effect and decent damage.
Kirin: Kirin jumps forwards like a beam with intertwining fire trail that do damage
Tiamat: A large aimable fire breath, covers a large area but very little knockback.
Juptier: A quick hail of homing projectiles, not very strong.
Atlanta: Arrows from the top of the screen, no knockback, but do cause flinching?
Procne: A large-ish Tornado with a vacuum effect, does little damage but launches them upwards.
Mercury: A spray of water forwards, akin to Flamethrower or the like.
Nereid: Tidal waves to either side, no damage but can push anyone on the platform off the sides.
Neptune: Several beams of water fall from the sky in random locations.
Grab would be psyenergy catch and his Final Smash would be Meggido or Odyssey.
Of course this moveset doesn't consider custom moves, and I have no idea how that would work, but hey, the discussion wasn't that long
.