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Character Isaac appearance.png
Full red heartFull red heartFull red heart
Table dividing line 1.png
Challenge Number
Starting Items
8-10 random items
Available Rooms
Item Pool Treasure Room.png: no          Item Pool Shop.png: yes
Laz Bleeds More! Character Lazarus icon.png Laz Bleeds More!
Unlock Method

Backasswards Defeat ??? or The Lamb

Added in Afterbirth †

Backasswards is challenge #31. Isaac starts with 8-10 random items, and starts on the Mega Satan boss fight. The goal is to play the floors backward, hence the challenge's namesake. Every floor ascended will cost one Heart Container(if the player has no Red Hearts, it will take a Soul Heart instead), and Removed in Repentancethe oldest item in the inventory. The player starts each floor with a boss fight (except the Dark Room Dark Room, which can be immediately completed), and will have to find the "starting room" to ascend a beam of light to the "previous" floor, similar to the effect of Dad's Note.

Difficulty[edit | edit source]

Starting with a random selection of items, and starting on the Mega Satan boss fight makes this challenge very difficult at first. If Mega Satan and Satan can be defeated, the rest of the challenge becomes significantly easier.

Strategy[edit | edit source]

  • Try to get some really powerful few-item synergies. Resetting is a perfectly good way to ensure good items.
    • Since Isaac will have at least 10 Red Heart containers from the start, 15►Pyromaniac Pyromaniac and items that grant exploding shots (15►Ipecac Ipecac, 15►Dr. Fetus Dr. Fetus, and 15►Epic Fetus Epic Fetus) combined is gamebreaking since as long as he gets caught by his explosions, he can heal indefinitely. They also do plentiful damage to enemies and can open closed doors. Isaac also can heal from Mega Satan's rock waves and mini-bosses spawned by him which spawn ignited Bombs, Troll Bombs or Megatroll Bombs.
    • Having 15►Gnawed Leaf Gnawed Leaf and something that can do damage while not moving, such as 15►Daddy Longlegs Daddy Longlegs, 15►Dead Bird Dead Bird, or 15►Smart Fly Smart Fly, can basically guarantee an eventual win. Damaging orbitals are also a big help.
    • 15►The Wafer The Wafer is an extremely useful item to receive in this challenge as well.
  • Going up a floor will remove one heart container and one passive item. If Isaac only has one red heart container, something as simple as leaving the floor itself will end the run.
  • With resurrection or teleportation items (such as Teleport or Cursed Eye), it's possible to skip boss rooms by dying as being resurrected puts Isaac outside of the room rather than back on the previous floor.
    • Despite this, do not get the 15►Dead Cat Dead Cat. If attempting to move onto the next floor while only having 1 HP, Isaac will instantly die instead of progressing, wasting one of his lives in the process.
    • Likewise, do not get Ankh. If resurrected as ???, each time ascended a floor a Soul or Black Heart will be lost, increasing the difficulty of the challenge.
  • Shops spawn as normal above The Womb The Womb.
  • 0 - The Fool 0 - The Fool and Mom's Hand are both quick ways to get to the starting room.
  • Rune of Ehwaz Rune of Ehwaz and 15►We Need to Go Deeper! We Need to Go Deeper! generate closed exits to the next floor, so they cannot help Isaac skip the current floor.
  • Items to be removed first are the "first" items picked up. This is the item in the rightmost column, in the lowest row of that column. If powerful items are shown there, it is best to restart.
    • 15►Halo of Flies Halo of Flies will take two entire floors to be removed. Only one fly will be lost per floor.
  • Removed in Repentance If a Mom's Dressing Table spawns in the starting room, its icon will show up on the map even if the starting room has not been visited yet. This makes finding the passage to the previous floor significantly easier.
  • If an Added in Repentance15►R Key R Key is used, it teleports Isaac back to the Mega Satan fight.

Reward[edit | edit source]

Bugs[edit | edit source]

Bug Bug! While entering an exit to the previous floor, if the player kills the process (isaac-ng.exe) during the versus screen before a boss fight, re-entering the game will lead Isaac to the starting room of the previous floor instead of the boss room. This allows the player to finish the challenge pretty easily without any actual fights.
Bug Bug! Sometimes the layout of the rooms makes traversing to the previous floor impossible. There might be a hole where the light is supposed to be and without flying, makes the run impossible to beat.
Bug Bug! If Isaac is teleported into the I AM ERROR room on the final floor of the challenge, there will be no exit, making the run impossible to beat.
Bug Bug! After the Mega Satan fight the player may start the following floors already in the beam of light making the Mega Satan fight the only one in the challenge. If the player doesn't have enough health to make it to The Basement 1, the run is over. If the player has enough health to make it to The Basement 1 they will be unable to move, to rectify this, simply exit the run, re-enter it and claim the reward.

MainPageChallenges.png Challenges MainPageChallenges.png

1. Pitch Black 2. High Brow 3. Head Trauma 4. Darkness Falls 5. The Tank 6. Solar System 7. Suicide King
8. Cat Got Your Tongue 9. Demo Man 10. Cursed! 11. Glass Cannon 12. When Life Gives You Lemons 13. Beans! 14. It's in the Cards
15. Slow Roll 16. Computer Savvy 17. Waka Waka 18. The Host 19. The Family Man 20. Purist
21. XXXXXXXXL 22. SPEED! 23. Blue Bomber 24. PAY TO PLAY 25. Have a Heart 26. I RULE! 27. BRAINS!
28. PRIDE DAY! 29. Onan's Streak 30. The Guardian
Afterbirth †
31. Backasswards 32. Aprils Fool 33. Pokey Mans 34. Ultra Hard 35. Pong
36. Scat Man 37. Bloody Mary 38. Baptism by Fire 39. Isaac's Awakening 40. Seeing Double 41. Pica Run 42. Hot Potato
43. Cantripped! 44. Red Redemption 45. DELETE THIS
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