How to Isaac

The Binding of Isaac, rebuilt in 3D inside How to Fish. Fight through Isaac's basement in first person with How to Fish's real guns, using Isaac's real rooms, monsters, bosses, items and music, read straight from your own copy of Isaac.

How to play

1. Press Play. Melty starts How to Fish with the mashup installed.
2. On How to Fish's main menu, click HOW TO ISAAC.
3. Pick HOW TO FISH on Isaac's own "WHO AM I?" character select and start your run.

The very first launch reads your Isaac files once (about 15 seconds). Solo only.

The run

• Five floors: Basement, Caves, Depths (Mom), Womb (Mom's Heart), then The Chest against ??? (Blue Baby).
• Isaac's real rooms, built in 3D from Isaac's own layouts: normal rooms, long and tall rooms, big 2×2 rooms and narrow corridors, with Isaac's floors, walls, doors, rocks, poop, TNT, spikes and pits.
• 38 of Isaac's monsters and 7 bosses (Monstro, The Duke of Flies, Gurdy, Peep, Mom, Mom's Heart, ???), with their real sprites, animations, health, sounds and music.
• Every room you clear drops a reward: coins, a heart, a key, dynamite, a chest or a gold chest.

Every kind of Isaac room

• Treasure rooms, shops and boss rewards.
• Secret and super secret rooms, placed by Isaac's own rules and invisible on the minimap until you're inside. Blow the wall open with dynamite to get in.
• Libraries behind a key door, and sacrifice rooms whose spikes pay out more the more you bleed.
• Devil and angel rooms, by Isaac's rules. From Caves I on, beating the boss may open a deal door. Your chance is far better if you took no red heart damage on the floor or in the boss fight. Angel rooms appear only after you've seen a devil room and never taken a deal. Devil items cost heart containers.

Isaac's items and hearts

• Nearly 150 of Isaac's items, each only in its real Isaac pool (treasure, boss, devil, angel, secret, library, golden chest). They really change your damage, fire rate, shot speed, range, speed and luck.
• Shot effects apply to every gun you hold, now and later: homing, piercing, spectral, poison, burning, slowing, freezing, fear, explosive shots and more.
• Active items charge as you clear rooms. Press G to use them.
• Your health is Isaac's hearts: red, soul, black, bone, eternal and rotten hearts, plus Holy Mantle, extra lives and the other heart items. How to Fish's own health and hunger are switched off during a run.

How to Fish's guns

• Pistol, SMG, Shotgun, Bow, Knife, Brass Knuckles, Sniper Rifle and Assault Rifle, with How to Fish's own damage. You start with the Pistol, and each boss drops a new gun, stronger on later floors.
• Dynamite blows up monsters, rocks, pots, poop and secret walls. Carry as many as you find.
• Shops sell How to Fish's real gun attachments (Laser Sight, Red Dot Sight, Compensator, Extended Mag, Sniper Scope, Suppressor, Bullet Upgrade), fitted straight onto the gun in your hands. Isaac's coins are your money.

On screen

Isaac's heart bar, a minimap with an arrow showing where you're facing, your collected items and stats, your active item's charge, your gun's stats and an ammo counter. Press F8 for a testing menu.

What you need

• How to Fish and The Binding of Isaac: Rebirth (with Repentance), both installed from Steam or another official store.
• Pirated copies of either game are not supported and will not work. The mashup reads your own legitimately installed games. Nothing from either game is included in this download.

Still a work in progress: Mega Satan and Delirium aren't in yet.

Credits: The Binding of Isaac: Rebirth by Edmund McMillen and Nicalis. How to Fish by Dazed Games. BepInEx (MIT) is the mod loader.