Quick Guide
- Completion marks appear on a character's post-it note, tracking bosses defeated.
- Each major boss has a corresponding mark, earned by defeating them with a specific character.
- Hard mode clears grant bloody marks and unlock powerful items like Mega Mush.
- Prioritize specific boss clears for essential unlocks like the D6 or Mom's Knife.
Welcome, fellow Isaac players, to a comprehensive guide on one of the most crucial aspects of progression in The Binding of Isaac: Repentance: understanding the binding of isaac repentance steam bosses and marks. Whether you're a newcomer trying to make sense of the character selection screen or a seasoned veteran aiming for Dead God, mastering completion marks is key to unlocking new items, characters, and challenges. These marks are more than just bragging rights; they represent significant milestones that directly impact your game's content and your ability to tackle increasingly difficult runs.
This guide will break down what completion marks are, explain each boss that contributes to them, and highlight why certain boss clears are essential for your overall progression.
What Are Completion Marks?
Completion marks are visual indicators found on a small "post-it note" in the top-left corner of the character selection screen. Each character has their own unique post-it note, and the marks on it denote which major bosses you've defeated with that specific character. These marks are vital for tracking your progress and, more importantly, for unlocking a vast array of items, trinkets, and even new characters.
The game features twelve distinct completion marks, with two additional ones introduced in the Repentance expansion. Each mark corresponds to a specific final boss or challenge. Successfully defeating a boss in normal mode will add a black-outlined mark to your character's post-it note. Conquering the same boss in hard mode will turn that mark "bloody," signifying a more challenging achievement and often leading to exclusive unlocks.
The Main Path Bosses and Their Marks
Several bosses represent the core progression paths in The Binding of Isaac: Repentance. Defeating these bosses typically opens up new routes or rewards.
Mom's Heart / It Lives
This is often the first completion mark players earn.
- Boss: Mom's Heart / It Lives
- Mark: A heart symbol.
- Access: After defeating Mom, you'll face Mom's Heart in the Womb II. After defeating Mom's Heart 10 times, it transforms into It Lives.
- Significance: Defeating Mom's Heart/It Lives is a prerequisite for accessing many subsequent paths. For instance, after beating It Lives, the beam to the Cathedral or the trapdoor to Sheol will always spawn, depending on whether you received an Angel or Devil Deal after the Mom's Heart fight.
Isaac
The boss of the Cathedral.
- Boss: Isaac
- Mark: A tear symbol.
- Access: Reach the Cathedral by entering the light beam after defeating Mom's Heart/It Lives (requires an Angel Deal, or will always spawn after 11 Mom's Heart/It Lives clears).
- Significance: Defeating Isaac five times unlocks The Polaroid, a key item for accessing The Chest.
Satan
The boss of Sheol.
- Boss: Satan
- Mark: A pentagram symbol.
- Access: Reach Sheol by entering the trapdoor after defeating Mom's Heart/It Lives (requires a Devil Deal, or will always spawn after 11 Mom's Heart/It Lives clears).
- Significance: Defeating Satan five times unlocks The Negative, a key item for accessing The Dark Room.
Blue Baby (??? / The Chest)
The final boss of The Chest.
- Boss: Blue Baby (also known as ???)
- Mark: A cross symbol.
- Access: After defeating Isaac in the Cathedral, if you have The Polaroid (unlocked by beating Isaac 5 times), you can enter The Chest.
- Significance: Unlocks various items and contributes to the overall completion of the game.
The Lamb (The Dark Room)
The final boss of The Dark Room.
- Boss: The Lamb
- Mark: A ram's head symbol.
- Access: After defeating Satan in Sheol, if you have The Negative (unlocked by beating Satan 5 times), you can enter The Dark Room.
- Significance: Similar to Blue Baby, this mark is crucial for full game completion and various unlocks.
Specialty Bosses and Their Challenges
Beyond the main progression paths, several unique bosses offer distinct challenges and their own completion marks.
Mega Satan
A powerful, optional boss.
- Boss: Mega Satan
- Mark: A larger, more ornate pentagram.
- Access: Can be fought on either The Chest or The Dark Room floors. To unlock his gate, you must have previously defeated The Lamb or Blue Baby. To enter, you need both Key Pieces, obtained by blowing up two Angel Statues and defeating Uriel and Gabriel in a single run.
- Significance: Defeating Mega Satan is a significant achievement and contributes to unlocking the "Dead God" achievement.
Boss Rush
A timed challenge.
- Boss: Boss Rush (a series of 15 waves of bosses)
- Mark: A stopwatch symbol.
- Access: Appears as a special room if you defeat Mom within 20 minutes of starting your run.
- Significance: Rewards you with an item and a completion mark.
Hush
A hidden boss in the Blue Womb.
- Boss: Hush
- Mark: A tear with a question mark.
- Access: The door to the Blue Womb appears if you defeat Mom's Heart or It Lives within 30 minutes. Inside, a trapdoor leads to the Hush fight. This floor contains valuable shops and item rooms.
- Significance: Defeating Hush unlocks the Void portal, a gateway to Delirium.
Ultra Greed (Greed Mode)
The final boss of Greed Mode.
- Boss: Ultra Greed
- Mark: A coin with a dollar sign.
- Access: Beat him at the end of a Greed Mode run.
- Significance: Essential for unlocking characters like Keeper and contributing to the Greed Donation Machine.
Delirium
The chaotic final boss of the Void.
- Boss: Delirium
- Mark: A glitching, distorted face.
- Access: The Void floor is typically accessed via a portal that can spawn after various bosses (5% after Mom, 10% after Mom's Heart/It Lives, 50% after Isaac or Satan, 20% after Blue Baby or The Lamb, 50% after Mega Satan). The only guaranteed way to find the portal is by defeating Hush, after which a door at the top-right of the Hush room leads directly to the Void portal.
- Significance: A true test of skill, defeating Delirium is a major step towards 100% completion.
Repentance-Specific Bosses: Mother and The Beast
The Repentance expansion introduced two new, incredibly challenging final bosses, each with their own complex access methods and completion marks.
Mother (The Corpse)
A grotesque, powerful boss.
- Boss: Mother
- Mark: A knife symbol.
- Access: This path requires collecting two Knife Pieces: one on Downpour II and one on Mines II. With both pieces, you can enter a special door in Mausoleum II after defeating an alternate Mom, leading to an alternate Mom's Heart fight. Defeating this version of Mom's Heart opens a trapdoor to The Corpse floors, culminating in the Mother fight.
- Significance: A crucial mark for unlocking tainted characters and other Repentance-exclusive content.
The Beast (Home)
The true final boss of the game.
- Boss: The Beast (preceded by Dogma)
- Mark: A burning heart with horns.
- Access: This path begins by defeating Mother. After doing so, a "strange door" will appear in Depths II in subsequent runs. To enter this door, you need either The Polaroid, The Negative, or the Faded Polaroid trinket. Entering teleports you to Mausoleum I, where you take an item pedestal instead of fighting a boss. This leads to the Ascension floors and finally to Home, where you face Dogma and then The Beast.
- Significance: Defeating The Beast is the ultimate challenge and unlocks the final set of tainted characters and the highest tier of completion.
Hard Mode and Bloody Marks
While normal mode clears award standard completion marks, defeating these bosses in Hard Mode grants "bloody" marks. These bloody marks are essential for unlocking some of the most powerful items in the game and are a requirement for achieving "Dead God" status.
- Bloody Marks: Earned by defeating any of the bosses listed above while playing on Hard Mode.
- Unique Hard Mode Unlocks:
- Ultra Greedier: Unlocked by donating 500 coins to the Greed Donation Machine. This harder version of Greed Mode's boss awards a unique bloody mark.
- Mega Mush: Unlocked by getting all hard mode completion marks as all non-tainted characters. This item provides a temporary, massive boost to stats.
- Death Certificate: Unlocked by getting all hard mode completion marks for all characters (including tainted characters). This incredibly rare item allows you to pick up any item in the game for one run.
Prioritizing Key Unlocks for Progression
With so many bosses and marks, it can be overwhelming to know where to focus. Here are some critical unlocks to prioritize for a smoother and more powerful gameplay experience in The Binding of Isaac: Repentance:
- D6 (Isaac): Beat Isaac with Blue Baby. The D6 is an active item that allows you to reroll items, making Isaac significantly stronger and more versatile.
- Wooden Nickel (Keeper): Beat Isaac with Keeper. The Wooden Nickel is crucial for Keeper, giving him a chance to spawn a coin on use, which is vital for his health management.
- Mom's Knife (Isaac): Beat Satan with Isaac. Mom's Knife is arguably one of the most powerful and sought-after offensive items in the game.
- Missing Poster (The Lost): Beat The Lamb with Isaac. This trinket is necessary for unlocking The Lost, a challenging but rewarding character.
- Lilith (Azazel): Beat Ultra Greed with Azazel. Lilith is a unique character who controls familiars, offering a different playstyle.
These specific boss clears, particularly on hard mode, pave the way for unlocking powerful items and characters that will fundamentally change your runs and improve your chances of success.
Focus on completing one character's post-it note at a time, especially on Hard Mode.
This systematic approach helps you track progress, unlock character-specific items efficiently, and build momentum towards the ultimate "Dead God" achievement.
Understanding the binding of isaac repentance steam bosses and marks is fundamental to navigating the game's complex progression system. Each mark tells a story of a challenge overcome and a step taken towards unlocking the full potential of this expansive roguelike. By systematically tackling these bosses and their associated paths, you'll steadily unlock the tools and characters needed to conquer even the most daunting challenges Repentance throws your way.
Frequently Asked Questions
What are completion marks in The Binding of Isaac: Repentance?
Completion marks are symbols on a character's "post-it note" that indicate which major bosses or challenges you have defeated with that specific character. They are essential for unlocking new items, characters, and progressing your save file.
How do I get bloody completion marks?
Bloody completion marks are earned by defeating a boss in Hard Mode. These marks are typically required for the most significant unlocks, such as Mega Mush and Death Certificate, and are crucial for achieving 100% completion.
Which bosses are included in the binding of isaac repentance steam bosses and marks?
The game includes marks for Mom's Heart/It Lives, Isaac, Satan, Blue Baby, The Lamb, Mega Satan, Boss Rush, Hush, Ultra Greed, Delirium, Mother, and The Beast. Each represents a significant milestone in your progression.
Why should I prioritize specific boss clears?
Prioritizing certain boss clears leads to unlocking powerful items (like the D6 or Mom's Knife) or crucial characters (like The Lost or Lilith) early on. These unlocks can significantly enhance your runs and make subsequent challenges more manageable, accelerating your overall progression in The Binding of Isaac: Repentance.