Binding of Isaac: Rebirth Wiki

(in Afterbirth † and Repentance)

Ultra Hard is Challenge #34. Isaac begins with both halves of the key for the Mega Satan Head ingameMega Satan battle and has to beat Mega Satan through the Dark Room.

Difficulty[ | ]

This challenge, like the name suggests, is extremely difficult:

  • All enemies with champion forms, including bosses, will be champions.
    • Champions will not drop any collectibles.
    • Ultra Hard is the only place in the game where "Rainbow" champions are not limited by time constraints and can appear early-game.
  • The player suffers from the following curses each floor: Curse of the LabyrinthCurse of the Labyrinth, Curse of the BlindCurse of the Blind, Curse of the LostCurse of the Lost, Curse of the MazeCurse of the Maze
    • These curses cannot be stopped through the usual methods of removing curses, such as the Rune of DagazRune of Dagaz, Collectible Black Candle iconBlack Candle or (in Repentance)Collectible Genesis iconGenesis.
    • In addition to the four curses, the player may additionally suffer from either Curse of the Unknown or Curse of Darkness, which can be removed through usual means.
  • Hearts of any kind – red, soul, black, eternal, bone, golden, blended and rotten hearts – do not appear on this run.
    • Hearts can still be obtained through passive items that grant them upon collection, such as Collectible Super Bandage iconSuper Bandage or Collectible Latch Key iconLatch Key.
    • Items and cards that normally drop hearts such as V - The HierophantV - The Hierophant tarot card will not drop any hearts. Using an Ace of HeartsAce of Hearts card will consume all pickups in the room, and not drop any hearts.
    • However, items that add hearts directly to the player's count (such as Balls of Steel or the Collectible Satanic Bible iconSatanic Bible) will work.
    • For example, Collectible The Gamekid iconThe Gamekid will give you hearts upon use, but Collectible Little C.H.A.D. iconLittle C.H.A.D. will not give you hearts.
  • Every boss fight that can be, will be double trouble.
    • Since the Basement can't have double trouble bosses, these don't start until CavesCaves.
  • Only Collectible The Negative iconThe Negative drops after killing Boss Mom ingameMom.
    • This forces the player to progress through SheolSheol and the Dark RoomDark Room to fight Mega Satan.
      • (except in Repentance) Even though the option to proceed upward through the CathedralCathedral is presented, the run will end after defeating Isaac and touching the chest will not give the player credit for completing the challenge.
        • The player can also beat the challenge by defeating Boss Delirium ingameDelirium.
          • Some players report no victory trophy spawning after defeating Delirium, under unknown conditions. It may not be safe to attempt this route.
  • If the player manages to defeat Boss Hush ingameHush, the entrances to the (except in Repentance) CathedralCathedral, SheolSheol, and The VoidThe Void appear.
    • (in Repentance)Defeating Delirium by traveling to The Void after defeating Hush spawns the trophy. Collecting it will still complete the challenge as normal.

Strategies[ | ]

  • Attempt to find valuable items from the two items rooms that appear in the Basement.
  • The Collectible D10 iconD10 can be surprisingly helpful; most of the time, it will reroll enemies into non-champion forms, and as the D10 can never reroll enemies into portals, it makes managing rooms with portals much easier.
    • (in Repentance) The D10 rerolls champion enemies into new champion enemies. Additionally, portals no longer spawn outside of The VoidThe Void.
  • The Collectible Glowing Hourglass iconGlowing Hourglass will allow the player to retry difficult rooms, avoid detrimental items, and peek at pills without the risk of harmful effects.
  • Trinkets that drops hearts as pickups such as Bloody PennyBloody Penny or Monkey PawMonkey Paw are useless in this challenge. However, those that directly heal such as Isaac's ForkIsaac's Fork or Stem CellStem Cell will still function.
  • Collectible PHD iconPHD is very valuable, as it reveals all pills, replaces detrimental pill effects with positive ones, and heals two red hearts upon pickup.
  • Hematemesis is a major problem in this challenge as it drains all your red hearts and does not give them back.
  • (except in Repentance)Items that reroll the player such as the Collectible D4 iconD4 and the Collectible D100 iconD100 can be used to amass health very quickly, as hearts generated from items are not removed if the items that granted them are rerolled.
    • (in Repentance)Items lost from the Collectible D4 iconD4 and the Collectible D100 iconD100 now remove associated hearts.
  • (except in Repentance)The Collectible Clicker iconClicker can potentially transform Isaac into Character Keeper iconKeeper, allowing him to heal with coins. That said, using it will remove your most recently collected item, so it shouldn't be used if it would remove a powerful item or Collectible Key Piece 2 iconKey Piece 2.
    • (in Repentance) Clicker can no longer spawn in challenges.
  • Look for LibraryLibrary and Bedrooms. Both of these rooms contain resources that can replenish the player's health.
  • Rainbow PoopRainbow Poops can be destroyed to fully heal the player.
  • Bombing Tinted Rocks is much less beneficial for the player, as soul hearts will not drop from them.
    • Tinted Rocks can still contain Collectible The Small Rock iconThe Small Rock, however, so if the player has a surplus of bombs or another way to destroy rocks, there is no reason to not destroy them.
  • Deals found in Devil RoomDevil Rooms are generally not worth taking. It may be preferable to pursue Angel RoomAngel Rooms instead, as the player already has both key pieces, which greatly increases their chances of spawning. Due to no Soul hearts or Black hearts being able to spawn naturally, taking damage and lowering the chance for a Devil / Angel room is very common. Make sure to find items that give these hearts such as Collectible Book of Revelations iconBook of Revelations or Collectible Satanic Bible iconSatanic Bible.
    • One-heart deals are almost never beneficial — many one-heart deals do not pay for themselves, whether that be in health or other effects. Avoid taking one-heart deals unless you are confident that they are worth their cost.
    • Two-heart deals are very powerful, such as Collectible The Pact iconThe Pact and Collectible Brimstone iconBrimstone. Be wary that Collectible Abaddon iconAbaddon can remove the player's red hearts, making items such as Collectible Pyromaniac iconPyromaniac, Collectible Yum Heart iconYum Heart and Collectible Placenta iconPlacenta useless until the player regains red hearts.
      • Judas' TongueJudas' Tongue and (in Repentance)Your SoulYour Soul will hide two-heart deals due to Curse of the Blind. Therefore, if you plan to use them, you should make sure to drop the trinket once you enter the devil room to be sure if you're actually getting a 2 heart deal.
    • (in Repentance) Satanic Bible now changes the Boss RoomBoss Room item into a Devil Deal, which depending on the item cost (as 2 heart deals generally provide better items), is not recommended
    • If Red ChestRed Chests spawn in the Devil Room, be wary of picking up any items that they may contain. The Red Chest item pool contains powerful items such as Collectible Dead Cat iconDead Cat but also contains potentially run-ruining items such as Collectible Cursed Eye iconCursed Eye and Collectible Curse of the Tower iconCurse of the Tower.
  • Do not enter Curse RoomCurse Rooms and do not use Sacrifice RoomSacrifice Rooms.
    • Curse Rooms very rarely contain a worthwhile item, and as Curse of the Blind is in permanent effect, it is impossible to tell if an item in a Curse Room contains a good item, such as Collectible Dead Cat iconDead Cat, or a bad item, such as Collectible Curse of the Tower iconCurse of the Tower.
    • Sacrifice Rooms do allow the player to potentially obtain a powerful Angel RoomAngel Room item; however, spending at least three full hearts for a chance at getting an item is almost always not worth it, especially as hearts do not naturally drop. Additionally, there is no reason to fight the angels, as the player already has both key pieces, and there is no reason to teleport early to the Dark Room and skip multiple Treasure Rooms, as the player is forced to take Collectible The Negative iconThe Negative anyways.
  • (except in Repentance)The Colorful Baby, which can be utilized in co-op mode, makes the Ultra Hard challenge trivial, as its healing effect can be used infinitely.
  • (in Repentance)Due to the permanent Curse of the Blind and the inability for hearts to drop, Collectible Binge Eater iconBinge Eater is an extremely powerful item as long as you can time the item swapping properly. This removes the worry of most harmful items while supplying a lot more healing and stats, and even allowing Devil Deals to be utilized to their fullest extent. The only drawback is the fact it is from the Secret Room pool, therefore making it very hard to come across. If you have the patience to farm Secret Rooms for this item, it can essentially guarantee a win.
  • (in Repentance)Collectible Shard of Glass iconShard of Glass is a very dangerous item in this challenge, as once damaged, there are no ways to stop the health draining effect unless you find an HP up, as heart pickups of any kind cannot spawn in Ultra Hard.

Reward[ | ]

Trivia[ | ]

  • Despite being the "Ultra Hard" challenge, this challenge is actually played in Normal Mode. Although it is not as noticeable in Afterbirth, in Repentance, it is far easier to notice due to the lowered shot speed of many enemies.