Bloody Mary

[Ender]

Did u beat it? what was strategy ? What did you do that I am not? How many controllers did you break while trying to beat it?

[left 4 edge]

placenta = ez win

[RZA]

Originally posted by G:

placenta = ez win

Or old bandage (less time consuming)

[Rio]

I had some orbitals and a bunch of familiars. Its good to identify pills so you can find a full health pill. Even a strength card at floor start can save the day.

I know I had a lot of red hp and probably old bandage too.

I think I also gulped a few trinkets like rotten penny. Blood banks and sac rooms are your friends. And marrow as absolute god awful an item it is, its great for bethony as a angel/devil deal protector. I think I also had humbling bundle for 2 heart pickups.

If you can get bloody penny, you can be set pretty good.

Blood puppy at max level I think can drop hearts, but thats pretty risky.

[NBX]

After a number of failed attempts I got really lucky and got Blank Card + The Sun on the 3rd or 4th floor. Full heal & map reveal at the start of every floor, made the rest of the run very easy.

[ToxicBoo]

I just got lucky, found Red HP pretty fast on every floor with EZ first rooms, on Sheol I even found binge eater in the secret room right next to spawn for a full heal.

[Pastapockets]

Old bandage should patch things up.

[Omertoso]

people have already mentioned a bunch of great items and trinkets for this challenge, so I'll talk about something else.

exploration was key for me. explore the current floor completely before you go to the next one; the more red health you lose upon the next floor, the more damage and speed you get, and thus, the longer you can survive until you find health again. bomb clusters of mushrooms, skulls and polyps for pills, cards and health, respectively. check out shops for more pills and cards, plus health. if you have leftover health in the floor, using blood donation machines may net you a Blood Bag.

the wiki page for this challenge has a lot more item recommendations. I didn't even realize items that activate when taking damage could be so good with Blood Oath! Fanny Pack, and Cambion Conception, for example.
https://bindingofisaacrebirth.fandom.com/wiki/Bloody_Mary

[Unreal]

It was surprisingly easy to complete once I understood how it worked. Lost the first 2 runs cause I went blind 3rd was rather unlucky and got some trash items, 4th was the charm and the challenge was done.
Explore the whole floor before going to boss, you got the book of belial to brute force pretty much any room you might find.
It's not as difficult as annoying in case you don't find any red heart

[JellyPuff]

Eternal-, bone- and rotten-hearts can preserve your Angel Room chance, making super-secret rooms more desirable than usual. Though, eternal- and rotten-Hearts can't carry over to the next floor (turns into heart-container/gets removed via Blood Oath). You can still take them with you via Moving Box or the Myosotis trinket (the Forget Me Not-flower).

Speaking of which, these as well as The Jar (another common shop item) are generally really good (game-winning in fact), because you'll likely end up with a surplus of red-hearts thanks to Child's Heart, which you do not want to get rid of (except maybe for Mom's Locket or Bloody Penny).

Blood Oath is a win condition, if you have a way to easely heal it off after it procs.

[Ender]

Finally got it and in the same boat as some of you. Didnt realize how good items that give you stuff on damage were. Flying was the trick for me on this one I think though

[Match]

On early floors is easy to avoid damage - I got Magic Fingers later and used it to clear rooms until I got some heart drops

[dorosh.similar]

Just run this challenge for the first time in my life and passed. Red hearts are dropped every room, so it needs just beat the first room on a floor without taking damage. It is good to have some emergency card/rune/pill/active item for this.

[RZA]

Originally posted by dorosh.similar:

Just run this challenge for the first time in my life and passed. Red hearts are dropped every room, so it needs just beat the first room on a floor without taking damage. It is good to have some emergency card/rune/pill/active item for this.

Hol up, I don't think they drop for every room. At least that's how I remembered it.

[Rio]

The heart trinket is just increased chance for hearts you could still clear a whole floor and not see any or only very few.

[dorosh.similar]

Originally posted by Somescratchedupdisc:

Originally posted by dorosh.similar:

Just run this challenge for the first time in my life and passed. Red hearts are dropped every room, so it needs just beat the first room on a floor without taking damage. It is good to have some emergency card/rune/pill/active item for this.

Hol up, I don't think they drop for every room. At least that's how I remembered it.

Idk, but I replaced my 'heart' trinket with another one, and red hearts still dropped very often. And every first room red heart was dropped for sure. I just had Algiz for insurance.