Decoding Completion Marks in The Binding of Isaac: A Comprehensive Guide

The Binding of Isaac, a roguelike dungeon crawler, is renowned for its depth, replayability, and challenging gameplay. A core component of this experience is the system of completion marks. These marks serve as a visual representation of a player’s progress and achievements with each character. Understanding how to obtain and interpret these completion marks is crucial for unlocking new items, characters, and challenges. This guide provides a comprehensive overview of completion marks in The Binding of Isaac, covering their significance, acquisition, and the rewards they unlock.

What are Completion Marks?

Completion marks are visual indicators that denote a character’s successful completion of specific challenges or boss encounters. Each character in The Binding of Isaac can earn a set of marks, typically displayed on the character selection screen or on a post-run victory screen. These completion marks act as a roadmap, showcasing which bosses have been defeated and which challenges have been overcome with a particular character.

The importance of these marks extends beyond mere bragging rights. Earning specific completion marks unlocks new items, trinkets, characters, starting items, and challenges that significantly alter the gameplay experience. For dedicated players, achieving full completion across all characters becomes a primary goal.

How to Obtain Completion Marks

The process of obtaining completion marks involves defeating specific bosses or completing certain challenges with each character. The specific requirements may vary slightly depending on the version of The Binding of Isaac being played (e.g., Rebirth, Afterbirth, Afterbirth+, Repentance). However, the general principle remains the same: complete the designated task with a specific character to earn the corresponding mark. The most common bosses and challenges include:

Mom: Defeating Mom is usually the first major milestone.
Mom’s Heart/It Lives!: Defeating Mom’s Heart (or It Lives! in later versions) unlocks further progression.
Isaac: Defeating Isaac in the Cathedral.
Blue Baby (???): Defeating Blue Baby in Sheol.
The Lamb: Defeating The Lamb in the Dark Room.
Mega Satan: Defeating Mega Satan, a challenging optional boss.
Hush: Defeating Hush in the Blue Womb.
Delirium: Defeating Delirium, a difficult and unpredictable boss.
Mother: Defeating Mother via the Corpse path.
The Beast: Defeating The Beast via the ascent.
Challenges: Completing specific challenge runs.

To earn a completion mark, the character must defeat the specified boss *after* unlocking the ability to fight that boss. For instance, defeating Mom’s Heart unlocks the path to Isaac and Blue Baby. Defeating Isaac or Blue Baby then unlocks The Lamb and Mega Satan. Similarly, defeating Hush unlocks the path to Delirium.

Understanding the Completion Mark Grid

The completion marks are typically presented in a grid format, usually found on the character selection screen. Each column represents a specific character, and each row represents a specific boss or challenge. The presence of a mark in a particular cell indicates that the character has successfully completed that challenge. The visual representation of the marks can vary between versions of the game, but the underlying principle remains consistent.

Different versions of the game introduce new bosses and challenges, expanding the completion mark grid. For instance, Repentance adds new paths and bosses like Mother and The Beast, requiring players to earn additional marks to achieve full completion.

Specific Completion Marks and Their Requirements

Let’s delve into the specific requirements for earning each completion mark:

Defeating Mom

This is one of the first completion marks players will aim for. Mom is found at the end of the Caves/Catacombs II floor. Defeating her unlocks the next stage of progression.

Defeating Mom’s Heart/It Lives!

After defeating Mom, players must repeatedly defeat Mom’s Heart (or It Lives! in later versions) multiple times to unlock new floors and bosses. This is a crucial step in progressing through the game.

Defeating Isaac

To fight Isaac, players must enter the Cathedral after defeating Mom’s Heart/It Lives!. Defeating Isaac unlocks new items and further progression.

Defeating Blue Baby (???)

Similarly, to fight Blue Baby, players must enter Sheol after defeating Mom’s Heart/It Lives!. Defeating Blue Baby unlocks new items and further progression.

Defeating The Lamb

To fight The Lamb, players must defeat either Isaac or Blue Baby and then use a specific item (e.g., the Negative) to access the Dark Room. Defeating The Lamb unlocks new items and achievements.

Defeating Mega Satan

Mega Satan is an optional boss that requires specific steps to access. Players must collect two key pieces from Angel Rooms or Devil Rooms. Defeating Mega Satan unlocks powerful items and is a significant achievement.

Defeating Hush

Hush is found in the Blue Womb, accessible by defeating Mom in under 30 minutes. Hush is a challenging boss that requires careful planning and execution. Defeating Hush unlocks new items and challenges.

Defeating Delirium

Delirium is a notoriously difficult boss that can be accessed through various means, such as using a Void portal after defeating Hush or by encountering a random portal in the Chest or Dark Room. Delirium’s unpredictable attacks and ability to transform into other bosses make him a formidable opponent. Defeating Delirium unlocks significant rewards.

Defeating Mother

Mother can be found by taking the alternate path through the Downpour/Dross, Mines/Ashpit, and Mausoleum/Gehenna floors to reach Corpse. The fight against Mother is a multi-stage encounter that tests players’ skills and resource management. Defeating Mother unlocks new items and characters.

Defeating The Beast

The Beast is found at the end of the ascent, which starts after defeating Mom in Depths II or Necropolis II. The ascent involves a series of challenging floors and boss encounters. Defeating The Beast unlocks new endings and items.

The Significance of Completion Marks

As mentioned earlier, completion marks are not just for show. They are intrinsically linked to unlocking new content in The Binding of Isaac. The specific rewards for achieving each completion mark vary, but they often include:

New Items: Many items are unlocked by defeating specific bosses with certain characters. These items can significantly impact gameplay.
New Trinkets: Trinkets provide passive bonuses and can be essential for overcoming difficult challenges.
New Characters: Some characters are unlocked by achieving specific completion marks. These characters often have unique starting stats and abilities.
New Starting Items: Certain characters start with different items based on the completion marks earned.
New Challenges: Completing certain challenges unlocks new challenges, providing fresh gameplay experiences.

For example, defeating Isaac with a particular character might unlock a powerful new item that appears in future runs. Similarly, defeating The Lamb with a specific character might unlock a new trinket that provides a significant advantage. Unlocking new characters often requires completing multiple completion marks with existing characters.

Tips for Achieving Completion Marks

Earning all the completion marks in The Binding of Isaac can be a daunting task, requiring patience, skill, and a deep understanding of the game’s mechanics. Here are some tips to help you on your journey:

Understand Character Strengths and Weaknesses: Each character has unique strengths and weaknesses. Understanding these differences is crucial for planning your strategy. For example, Cain starts with a key and has increased luck, while Eve starts with the Whore of Babylon item but has lower health.
Prioritize Item Synergies: Experiment with different item combinations to discover powerful synergies. Some items work exceptionally well together, creating devastating effects.
Learn Boss Patterns: Each boss has unique attack patterns. Learning these patterns is essential for dodging attacks and minimizing damage.
Manage Resources Effectively: Carefully manage your health, keys, bombs, and other resources. Knowing when to use these resources can make the difference between victory and defeat.
Utilize Angel and Devil Rooms: Angel Rooms and Devil Rooms offer powerful items and upgrades. Weigh the pros and cons of each choice carefully.
Practice and Persistence: The Binding of Isaac is a challenging game that requires practice and persistence. Don’t be discouraged by failures. Learn from your mistakes and keep trying.

The Binding of Isaac: Repentance and Completion Marks

The Binding of Isaac: Repentance significantly expands the game with new characters, items, challenges, and bosses. This expansion also introduces new completion marks, adding to the overall complexity and replayability of the game. The addition of new paths and bosses like Mother and The Beast requires players to adapt their strategies and master new techniques to achieve full completion. [See also: Tainted Characters in The Binding of Isaac]

Repentance also rebalances existing items and characters, altering the difficulty of certain challenges. Some characters become more viable, while others require new approaches to succeed. This rebalancing adds another layer of depth to the game, encouraging players to experiment and discover new strategies.

Conclusion

Completion marks are an integral part of The Binding of Isaac, providing a tangible representation of a player’s progress and achievements. Earning these marks unlocks new content, enhances gameplay, and adds to the overall replayability of the game. By understanding the requirements for each mark and employing effective strategies, players can embark on a rewarding journey to achieve full completion. Whether you’re a seasoned veteran or a newcomer to the world of The Binding of Isaac, mastering the system of completion marks is essential for unlocking the game’s full potential. So, dive in, explore, and conquer the challenges that await, and proudly display your hard-earned completion marks!