Challenges

Challenges are unique runs in the game. Isaac typically starts each challenge with one or more specific items which makes normal play more difficult. With few exceptions, Treasure Rooms are not available during challenges. Each challenge unlocks new content for the game, such as runes when completed. Players, with the advent of modding, have created their own Custom Challenges too.

General Strategy

Most challenges are designed to increase the difficulty of the game in a unique fashion. This doesn't mean all challenges are difficult, however; challenges like Computer Savvy are quite easy to beat. Some challenges do compensate for this by being especially punishing; Solar System is a good example of this. Each challenge has certain strategies that can be employed to make the run easier. However, there are a few strategies that can apply to all challenges.

• Challenges can be played in co-op, allowing a second player to contribute to the run without being hindered in the same way Isaac is. This is especially useful in any challenge where Isaac is Blindfolded, as the second player will be allowed to fire tears normally.
  • If other players join the game in the first room for true co-op, they will not get to select a character and will be forced to play as the character the challenge has you play as, ex. for Blue Bomber, all players will be forced to play as ??? no matter what. (This excludes untrue co-op because of co-op babies.)
• Due to the lack of Treasure Rooms, Devil Rooms become much more valuable. Some challenges can be made much easier by making just one deal, but it is worth noting that other challenges reduce Isaac's health to the extent that Devil Deals become too risky.
  • Some rooms (including Crawl Spaces) may have Treasure Room items by default. Since these items are random, results can vary from run to run.
  • Because locked Treasure Rooms won't spawn, keys can be used far more liberally. Also, trinkets and items that generate more coins, along with upgraded Shops, can help Isaac acquire a greater range of powerful items.
• The Bible instantly kills Mom and Mom's Heart / It Lives. All challenges require defeating Mom, and most require defeating Mom's Heart or It Lives, making this an extremely powerful item, especially in challenges where Mom or Mom's Heart / It Lives is the final boss.
  • Pandora's Box will spawn The Bible if used in Womb II, Utero II, or Scarred Womb II, making it a reliable way to acquire The Bible.
• Curse Rooms can spawn items, making them valuable.
• In some challenges, Dice Rooms and the D4 are very useful, allowing that challenge's starting items to be rerolled, thus removing most of the difficulty. NOTE: This changes depending on the challenge. Most challenge pages contain details on the results of rerolling.
  • Butter! can also remove starter items.
• Blindfolded challenges are arguably the most difficult challenges due to Isaac's inability to fire tears. There are several methods to work around this.
  • Familiars can provide an alternative method of dealing damage. Powerful familiars like Daddy Longlegs, Lil Brimstone, and Incubus are therefore highly useful items.
  • The Boomerang, The Candle, and Red Candle are also useful for blindfolded challenges, since they recharge based on a timer, rather than an amount of cleared rooms.
  • Clicker can allow Isaac to change into Lilith, whose Incubus overrides the blindfolded effect by default.
  • Some spacebar items like Tammy's Head can be really helpful, providing an alternative method of dealing damage.
• Chaos is a powerful item in challenges, as it can allow powerful items to be found more commonly, such as in the Shop or after defeating bosses.
• Defeating a boss beyond the specified end of the challenge (e.g. defeating Mom's Heart when the goal is to defeat Mom) will still spawn the trophy.
  • In some longer challenges (e.g. XXXXXXXXL), using a Sacrifice Room until it teleports Isaac to the Dark Room is a viable strategy. Once in the Dark Room, the trophy can be spawned by defeating The Lamb.
    • In a similar vein, all runs can be completed by killing Delirium, meaning that the player can beat a challenge through an alternative method such as defeating Hush then traveling to The Void; however, this is generally extremely difficult given the restrictions challenges place on the player.

Notes

• Apart from the achievement related to beating the challenge, all achievements are locked. Also, no Donation Machines will appear in any challenge.
• The challenge reward will not be unlocked unless the trophy is picked up. If a Devil Room or Angel Room appears allowing Isaac to go to Sheol or the Cathedral, the unlock will be forfeited.
• Isaac will not start any challenge with The D6.

Challenges List

Name	Conditions	Goal	Unlocked by	Unlocks
1. Pitch Black	Curse of Darkness Curse of the Unknown : yes : no		Default	Rune of Hagalaz
2. High Brow	Starts with: Number One E Coli Butt Bombs Flush! Petrified Poop : no : yes		Default	Rune of Jera
3. Head Trauma	Starts with: Tiny Planet Soy Milk The Small Rock Iron Bar : no : yes		Default	Rune of Ehwaz
4. Darkness Falls	Starts with: Pentagram Dead Bird Whore of Babylon Razor Blade Sacrificial Dagger Dark Matter : no : yes		Defeat Mom's Heart 11 times Defeat Satan and ??? as Eve	Rune of Dagaz
5. The Tank	Starts with: Infamy Bucket of Lard Thunder Thighs Yum Heart : no : yes		Have 7 or more Red Heart Containers at one time	Rune of Ansuz
6. Solar System	Blindfolded Starts with: Distant Admiration Forever Alone Halo of Flies Transcendence : no : yes		Defeat Mom's Heart 3 times	Rune of Perthro
7. Suicide King	Starts with: Ipecac Mr. Mega My Reflection 1 random pill : no : yes		Defeat Mom's Heart 11 times	Suicide King
8. Cat Got Your Tongue	Blindfolded Starts with: Guppy's Hair Ball Guppy's Head Guppy's Tail : no : yes		Become Guppy	Rune of Algiz
9. Demo Man	Starts with: Dr. Fetus Remote Detonator Match Stick : no : yes		Defeat Mom's Heart 9 times	Chaos Card
10. Cursed!	Starts with: Blue Map The Compass Raw Liver Treasure Map Yum Heart Child's Heart Curse of the Cursed : yes : yes		Have 7 or more Red Heart Containers at one time	Credit Card
11. Glass Cannon	Starts with: Epic Fetus Loki's Horns : no : yes		Beat The Family Man (challenge #19) and defeat Lokii	Rules Card
12. When Life Gives You Lemons	Starts with: 9 Volt Habit Lemon Mishap 1 Lemon Party pill : no : yes		Default	Card Against Humanity
13. Beans!	Blindfolded Starts with: 9 Volt The Bean The Black Bean Butt Bombs Pyro : no : yes		Default	Burnt Penny
14. It's in the Cards	Starts with: 9 Volt The Battery Deck of Cards Starter Deck 2 random tarot cards : no : yes		Default	SMB Super Fan
15. Slow Roll	Starts with: Cupid's Arrow My Reflection Polyphemus : no : yes		Default	Swallowed Penny
16. Computer Savvy	Starts with: Spoon Bender Technology Technology 2 : no : yes		Default	Robo-Baby 2.0
17. Waka Waka	Starts with: Anti-Gravity Strange Attractor : no : yes		Default	Death's Touch
18. The Host	Starts with: The Mulligan Spiderbaby Tick : no : yes		Default	Technology .5
19. The Family Man	Blindfolded Starts with: BFFS! Brother Bobby Dad's Key Rotten Baby Sister Maggy : no : yes		Pick up both Key Pieces from the Angels in one run	Epic Fetus
20. Purist	: no : yes		Defeat Mom	Rune of Berkano
21. XXXXXXXXL	: yes : yes Every floor is the size of an XL Womb floor, but does not combine the floors of each chapter.		Defeat Mom	Gold Heart
22. SPEED!	: yes : yes Everything is sped up like the Broken Watch effect.		Defeat Mom	Get out of Jail Free Card
23. Blue Bomber	Blindfolded Starts with: Brother Bobby Kamikaze! Pyromaniac Mr. Mega : no : yes		Destroy 10 Tinted Rocks and defeat Mom's Heart 11 times	Gold Bomb
24. PAY TO PLAY	Starts with: Money = Power Sack of Pennies 50 coins : no : yes Every door costs 1 cent to enter. Isaac drops money when hit. Isaac dies if he run out of money.		Defeat Isaac as Cain	2 new pills
25. Have a Heart	Starts with: Charm of the Vampire : yes : yes Pennies drop instead of Red Hearts. Many items that restore Red Hearts have no effect.		Defeat Mom	2 new pills
26. I RULE!	Starts with: The Boomerang Key Piece 1 Key Piece 2 The Ladder Mom's Knife Trinity Shield : no : yes		Defeat ??? or The Lamb, and defeat Satan as Isaac Defeat Mega Satan	Poker Chip
27. BRAINS!	Blindfolded Starts with: 3 Bob's Brain Thunder Thighs : no : yes		Defeat Isaac 5 times	Stud Finder
28. PRIDE DAY!	Starts with: 3 Dollar Bill Rainbow Baby Rainbow Worm : no : yes Cannot drop or replace Rainbow Worm.		Defeat Mom	D8
29. Onan's Streak	Starts with: The Book of Belial Chocolate Milk : yes : yes Missing a shot deals damage to Judas.		Defeat Mom	Kidney Stone
30. The Guardian	Blindfolded Starts with: Holy Grail Isaac's Heart Punching Bag Spear of Destiny : no : yes Isaac's Heart will follow Punching Bag instead of Isaac.		Defeat Mom	Blank Rune
31. Backasswards	Starts with: 8-10 random items : no : yes All chapters progress in reverse order, losing 1 item and 1 Red Heart container each floor ascended.	Basement/ Cellar/ Burning Basement I	Defeat ??? or The Lamb Defeat Mega Satan	Laz Bleeds More!
32. Aprils Fool	: yes : yes The minimap displays the floor's layout accurately, but displays Isaac's position inaccurately. Pedestal items and pickups are not what they appear to be. Active items, pills, cards, and rune effects are randomized upon each use, making them very unreliable or deadly (for example Suicide King). Items with no charge time (i.e. How To Jump, IV Bag, etc) can be used repeatedly for random effects. Stoneys have a chance of being replaced by Cross Stonies. Every boss is The Bloat. Isaac's health is not what it appears to be. Key and bomb numbers are accurate.		Defeat Mom	Maggy Now Holds a Pill!
33. Pokey Mans	Starts with: Friendly Ball Mom's Eyeshadow : no : yes Each use of Friendly Ball causes a random monster to be spawned. Friendly Ball instantly charges once the spawned monster is killed.		Defeat Mom's Heart 11 times	Charged Key
34. Ultra Hard	Starts with: Key Piece 1 Key Piece 2 Curse of the Labyrinth Curse of the Blind Curse of the Lost Curse of the Maze : yes : yes All enemies spawn as champions if possible. Boss fights will be double trouble if possible. No heart pickups drop.		Defeat ??? or The Lamb. Possession of The Polaroid/ The Negative is required, barring getting to Dark Room through a Sacrifice Room. Defeat Mega Satan	Samson Feels Healthy!
35. Pong	Starts with: Cupid's Arrow Rubber Cement : no : yes Damage fixed at 100, tear delay fixed at 150.		Defeat Isaac 5 times	Greed's Gullet
36. Scat Man	Blindfolded Starts with: The Poop 9 Volt Skatole E Coli 3 Butt Bombs BFFS! Thunder Thighs Dirty Mind Mysterious Candy : no : yes		Default	Dirty Mind
37. Bloody Mary	Starts with: The Book of Belial Blood Bag Anemic Blood Oath Child's Heart 4 soul charges : no : yes		Defeat Mom's Heart/It Lives on hard mode as Lazarus, without dying, defeat Mom's Heart 11 times and unlock Blood Bag	Sigil of Baphomet
38. Baptism by Fire	Blindfolded Starts with: Urn of Souls Schoolbag Guppy's Paw Maggy's Faith : no : yes		Defeat Satan as Bethany, defeat Mom's Heart 11 times and unlock Maggy's Faith	Purgatory
39. Isaac's Awakening	Starts with: Spirit Sword Trinity Shield Mom's Bracelet : no : yes		Defeat Mother	Spirit Sword
40. Seeing Double	Starts with: Jacob: 20/20 Esau: 20/20 X-Ray Vision : no : yes		Defeat Mother	Broken Glasses
41. Pica Run	Starts with: Mom's Box Marbles Mom's Purse : yes : yes		Defeat Mom's Heart 11 times and Unlock Marbles	Ice Cube
42. Hot Potato	Blindfolded : no : yes		Use the Red Key or Cracked Key in Home as The Forgotten	The Chariot
43. Cantripped!	: no : yes		Use the Red Key or Cracked Key in Home as Cain	Justice
44. Red Redemption	Starts with: Dad's Key Red Key : yes : yes		Use the Red Key or Cracked Key in Home as Jacob and Esau	The Hermit
45. DELETE THIS	Starts with: TMTRAINER : yes : yes		Use the Red Key or Cracked Key in Home as Eden	Temperance