How To Unlock Every Final Boss in The Binding of Isaac Afterbirth+

So you’ve just beaten Mom for the first time. What’s next? Here’s how to reach every final boss in The Binding of Isaac Afterbirth+.

Edmund Mcmillen’s classic rogue-lite just keeps getting bigger. For beginners though, how to unlock all this new content can be quite the mystery. With so much of the game’s unlocks revolving around its bosses, there’s no better way for new players to learn, improve and unlock new goodies than defeating Isaac’s various final foes. 

Mom

First things first is the original final boss. Upon your first time loading the game, the only final boss available to you is Mom herself. This one’s simple – reach the sixth floor (Depths II) and explore until you find the boss room. 

Mom’s Heart

After you’ve defeated Mom for the first time, you’ll unlock The Womb. Reach the end of these new floors and you’ll come face to face (face to heart?) with this new, much harder final boss. 

Satan

Here’s where the game gets complicated. Many of the following bosses can be done in a different order than they’re listed here, but I think that this order makes the most sense. 

There’s a couple ways to reach Satan. Sometimes, after you’ve beaten Mom’s Heart, a devil door will appear in the room, instead of just the run-ending chest. The easiest way to get this devil door to appear is to avoid taking red heart damage through the entirety of Womb II. Walk into the devil room and fall into the trapdoor within.

In this new, ninth floor, Sheol, you can find your hardest boss yet waiting for you at the end. Satan can certainly be rough for newcomers, but with enough practice, you’ll be breezing through him like he’s an overgrown Larry Jr.

If you’re not quite adept enough yet to beat Womb II damageless, don’t worry! The second method of getting to Satan involves a lot less luck, and a lot more practice at beating Mom’s Heart. Once you’ve beaten the heart 11 (yes 11!) times, a trapdoor into Sheol is guaranteed to appear everytime the heart goes down. 

It Lives!

Beating Mom’s Heart 11 times brings some changes to the womb too. After 11 deaths, Mom’s Heart permanently disappears, instead being replaced by the slightly harder and much more horrific It Lives!. Thankfully, after 11 successful bouts against the heart, you shouldn’t have too much trouble slicing through its new, disgusting replacement. 

Isaac

Also coming to Womb II along with It Lives! is a bright light right next to the Sheol trapdoor. Stepping into this beam of light takes you up to a different 9th floor. The cathedral houses Isaac, a much easier boss than Satan, bringing with him a new host of unlockables. 

???

Nine floors deep into Isaac’s psyche, you might be tempted to think that you’ve reached the final level. However, Cathedral and Sheol will soon become only gateways to the first two ‘true’ final bosses you’ll unlock. Once you’ve beaten Isaac five times, The Polaroid will begin appearing after every Mom fight. Pick this up after beating Mom, and once you beat Isaac in the Cathedral, hop into the chest to be transported to the 10th floor – The Chest. Be sure to bring some keys to get your final items of the run, before finding the boss door to fight ???. Congratulations for beating your first true final boss!

The Lamb

The mirror to ???, The Lamb hides in The Dark Room, the 10th floor which hides behind Satan’s Sheol. Beat Satan five times, and then pick up The Negative after the Mom fight. Take The Negative all the way down to Satan, and head down further to fight The Lamb at The Dark Room’s end. 

Mega Satan

The hardest boss in the game before Afterbirth came along, Mega Satan remains the hardest to reach. There are two methods to reach him, but the easiest is through using angel rooms. Assuming you’ve unlocked either The Chest or The Dark Room, you’ll first have to spawn an angel room after an early boss fight. 

To spawn an angel room, you’ll have to spawn a devil room first, and then refuse to take any deals with the devil. The easiest way to spawn a devil room is through the method I mentioned during Satan’s section – avoid taking red heart damage throughout the entire floor.

By this point in your time with Isaac, this should be pretty easy to pull off on the Basement, Caves and Depths floors, so stay focused and you’ll get through. Once you’ve spawned the devil room and refused the deals, attempt to spawn another two floors later, again by avoiding damage. If luck is on your side (and it usually is with this method), an angel room will spawn, overriding the usual devil room appearance. 

Head on in, and grab your free item. But before leaving, commit blasphemy by setting off a bomb in front of the angel statue. By angering the angel, and beating it in the ensuing boss fight, you’ll get one half of Dad’s Key. Once you’ve gotten the first half, you’re all but guaranteed to gain access to Mega Satan, as Angel rooms are almost certain to appear (so long as you avoid that pesky red heart damage). 

Go through the process of spawning another angel room two or more floors later, and do the same again, killing the other angel within its room. Pick up the second half of Dad’s Key, and head all the way down to the 10th floor of your choosing. 

In the starting room of either 10th floor (I recommend The Chest) will be a large door at the top of the room. With Dad’s Key in tow, you’ll finally be able to gain access to this hidden chamber, and fight the colossal Mega Satan within it. Good luck!

Hush

Easier to unlock but much harder to beat than Mega Satan, Hush is the new final boss that came with Isaac’s Afterbirth expansion. Thankfully there’s only one requirement: reach and beat It Lives! In under 30 minutes. By doing this, a huge crack will form in the side of the It Lives! boss room, which leads to an alternate 9th floor, the Blue Womb. A floor with just one combat room and a wealth of items to prepare you sets the tone for the truly gruelling battle that is ahead of you. Unless you’ve swallowed the Limitless pill, don’t attempt Hush with a build that isn’t A-tier. 

Delirium

The new king of difficult Isaac bosses until the Repentance DLC hits consoles this year, you could argue that Delirium is the ‘truest’ final boss of Isaac. Existing on a new 11th floor, The Void, it’s obvious that Delirium is in a league of its own.

To reach The Void, you’ll have to take a void portal after one of the many final bosses you can fight on your way to a standard 10th floor ending. Here’s the rundown of possible portal locations and the chances that you’ll get to visit (and probably die to) Delirium. 

It Lives! : 10% chance

Isaac/Satan: 15% chance

Mega Satan: 50% chance

Hush: 100% chance

Long story short, if you want a guaranteed date with Delirium, Hush is your way to go. Don’t fear though. Although the road to Delirium is harsh, the boss fight itself is so hard that your build would have to be capable of beating Hush anyway in order to stand a chance. 

Once you get down to The Void, you’ll have to watch out for the fake boss doors. The Void is unique in that it has multiple boss rooms, with only one holding Delirium. Don’t fear though, as by this point your build will probably be carving through the other bosses like they’re made of red-hot mars bars. 

And that’s how to reach every final boss in The Binding of Isaac: Afterbirth+. Be sure to check in again with Gaming Exploits when Repentance hits consoles to see our guides on how to reach the new final bosses. 

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