Amon resisted Tarrlok's bloodbending hold. The effects of bloodbending can be resisted, and a bloodbender's hold can be broken when applied to a waterbender of similar or superior skill to the user.
Tarrlok couldn't bloodbend Amon because Amon was a stronger waterbender than Tarrlok. The only people who can resist bloodbending are stronger waterbenders. This is why Aang was able to resist Yakone while he was in the Avatar State. Because in that moment, Aang was the stronger waterbender.
As I understand it, Amon is using blood bending to cut off or damage his victim's chi paths - essentially, he's permanently chi-blocking them in order to prevent them from being able to bend. The damaged chi paths can be restored by energybending, but no other method is effective.
Amon is forced back to the window at the end of the corridor, but retaliates, using bloodbending to ensnare Korra. However, Korra is able to resist and forces her leg up and forward to launch a powerful air-kick at Amon, blasting him out the window and into the sea.
In the finale, Tarrlok specifically explained that Amon was somehow using his bloodbending to weaken the bending of those who fought him. That's why powerful bending attacks didn't faze him in earlier episodes, and that's why Mako's lightning didn't do serious harm to him.
Amon is exceptionally talented at bloodbending and is by far the most powerful bloodbender seen in The Legend of Korra or Avatar: The Last Airbender. He is so skilled at it that he can even remove a person's bending altogether by severing their connection with it through bloodbending.
After teaching her/energybending her, she enters the Avatar state. And as was said before, when entering the Avatar state, bloodbending is reversed, thus unblocking het bloodbend chi paths.
This technique, Bloodbending, could only be used with the influence of the full moon enhancing her abilities. Horrified by the idea of controlling another person's body, Katara is doubtful as to whether she should really learn about learning to master blood.
Amon harbored a severe abhorrence of benders and regarded bending as an "impurity" to be "cleansed". This stemmed from his belief that bending only caused suffering and that benders possessed an unnatural advantage over nonbenders.
174 AG. In 174 AG Wu and Korra managed to transform the Earth Kingdom into the Earth Federation and Wu abdicated. Four years later, Korra married Asami and two years later created the Global Assembly.
We only learn of bloodbending in “The Puppetmaster,” at the end of Book Three of ATLA, and it is never used again. However, in The Legend of Korra (LoK), bloodbending is banned by the United Republic of Nations through the efforts of Katara.
Amon and Yakone take the top two spots. Most peole would say Amon was more powerful than Yakone, considering Amon was capable of debending people with bloodbending and capable of using it subtly in hand-to-hand combat, but the scene we get with Yakone involves him bending dozens of people at once.
While Amon was indisputably the superior bloodebender and a far more dominating physical fighter, Katara's own skills in waterbending were above his own. Boomstick: Amon is a formidable martial artist and chi blocker, but his lack of waterbending put him at a disadvantage.
As you pointed out, all Waterbenders get an increased ability to control water during a full moon due to the moon's gravitational pull, however Yakone was simply already just an incredibly powerful Waterbender who trained intensely to achieve the ability to Bloodbend without the full moon.
Being able to bloodbend without a full moon may be achieved after training the taboo skill. Katara refused to use it in The Last Airbender due to her moral obligation, so she never got the chance to train it.
Aang : You did the right thing. Forgiveness is the first step you have to take to begin healing. Katara : But I didn't forgive him. I'll never forgive him.
Hakoda was Katara and Sokka's father and a prominent figure in his daughter's life. His departure from the Southern Water Tribe to fight in the Hundred Year War had a profound impact on Katara, who felt abandoned and betrayed by him, in spite of the fact that she knew his reasons for departing.
Amon. Amon was the most powerful bloodbender the Avatar had ever encountered, easily giving Hama, Katara, and his father Yakone a run for their money in this rare and dangerous bending subset.
Katara bloodbended the Fire Nation soldier who took her mother away. Similarly to Hama, Katara could easily bring down Ozai by using the bloodbending technique.
Even Aang, the avatar, and Zuko could only redirect lightning. It was incredibly powerful and only used for huge moments in the story. This is why when The Legend of Korra first debuted (and as new fans have rediscovered it on Netflix) many fans were confused why lightning bending seemed so commonplace.
Amon is probably the second most powerful villain in the Avatarverse. He can take away bending without energybending, is very speedy, and strong. People like to say that Aang would wipe the floor with Amon because he'd just go into the Avatar State and break out of the bloodbending like he did with Yakone.
Amons ability to take away someones bending is due to his ability to bloodbend. The statement from the wikia says He used “his mastery of bloodbending to "sever" an individual's bending connection by blocking their active chi paths, effectively achieving the same result as energybending”.
