Anders Breivik planned to behead Norway's former prime minister and use a lake around the island he attacked as a "weapon of mass destruction" to kill everyone, he told court on Thursday.
During his chilling testimony, the right-wing extremist said he believed "all political activists who choose to fight for multiculturalism are legitimate targets."
He killed 69 people on Utoya island, which was hosting a Labour party youth camp. Breivik told the court he also planned to execute Norway's former prime minister Gro Harlem Brundtland, who had visited the island ahead of the massacre, adding he wanted to post a film of her beheading online.
Speaking at the fourth day of his trial on Thursday the 33-year-old told the Oslo court he believed his chance of survival was 5% when he set off a bomb outside a government building in July last year, before travelling to attack a Labour party youth camp in Utoya.
"When I parked the car outside the government offices, I had expected a national alarm would be raised and three or four people would storm out.
"I would have a pincer movement against me and I would have to fight my way out of there.
"I had trained to get myself out of this situation and this is what I was simulating," he said.
There was weeping in court from the families of victims as he described the twin massacres, in Oslo and Utoya.
The court also heard about Breivik spent 16 hours a day playing the computer game World of Warcraft during a "sabbatical" from his business activities and how he "trained" for the attacks by playing Call of Duty: Modern Warfare.
"If you are familiar with a holographic sight, it's built up in such a way that you could have given it to your grandmother and she would have been a super marksman. It's designed to be used by anyone. In reality it requires very little training to use it in an optimal way. But of course it does help if you've practised using a simulator," he said.
The far-right extremist accused prosecutors of trying to ridicule him when they asked how he spent the New Year's Eve before his attack, saying "You're trying to make fun of me." He had previously told judges he was "social" and "when I party, I go all out. I do things very thoroughly."
During his fourth day in court a clearer picture emerged of how he meticulously planned his attacks, first deciding on taking violent action more than a decade before striking, in 1999 when he was just 20.
Five years before attacking the government building in Oslo he had scouted it out as a target. He also explained how he gave names to his weapons derived from Norse mythology. His handgun was named "Mjolnir" after Thor's hammer and his rifle "gungnir" after the spear of Odin.
The killer said it was "a European tradition"
Breivik also condemned the psychiatric report which judged him to be criminally insane, declaring it was a "fairytale" and "80% made up."
He divulged to prosecutors 50-60% of his manifesto, which he published online before carrying out the brutal killings, was "cut and paste" from other sources.
Breivik is expected to divulge further details about his family, life with his mother and the events leading up to his massacre of 77 people in July last year as he gives evidence on Thursday.
He told the court on Wednesday there were only "two just and fair" outcomes of his trial: "acquittal or capital punishment."
Breivik, who has admitted to the crimes and faces a 21 year jail sentence if found guilty, said: "I consider 21 years of prison as a pathetic punishment." Norway does not carry the death penalty.
Hesaid his attacks were inspired by "Serb nationalists" and that he distanced himself from "old school" right-wing ideology.
"The essence was to try to distance oneself sufficiently from national socialism because it was quite blood-stained," he told the court. "We felt it completely essential to do so. For the extreme right to be ever be able to prevail in Europe in the future, one had to distance oneself from the old school ideology."
The Serbs had a "crusader" mentality which he aspired to emulate, Breivik said.
He said he was more "liberal" than the Nazis and would allow a small number of non-Norwegans to live in the country.
The killer also told the court he admired al-Qaeda and Osama Bin Laden, explaining that nationalists had much to learn from them, despite his self-confessed Islamaphobia.
He told judges he was not scared of death and was "surprised" he survived his attacks in July last year.
"If I had feared death I would not have dared to carry out this operation," he said.
Earlier, Breivik refused to give details about his visit to London 10 years ago, during which he claimed an anti-Islamic organisation called the Knights Templar was founded.
Questioned by prosecution on whether he met fellow anti-Islamic activists including a character named 'Richard The Lionheart' in London in 2002, as detailed in his notorious manifesto, Breivik said there was a meeting but was evasive about the exact details.
"It is not in my interest to shed light on details that could lead to arrests," he told the Oslo court on Wednesday.
"There is nothing that is made up, but you have to see what is written in a context. It is a glorification of certain ideals," Breivik said in relation to his manifesto.
But he was warned by the judge that a refusal to give details in response to questioning could be used against him.
Prosecutors showed images of Breivik taken from his manifesto. A badge on the uniform read "Marxist Hunter"
Appearing on the third day of his trial for the murder of 77 people in July last year, the 33-year-old did not discuss claims in the document about his "English protestant host" and the founding session of the Knights Templar group.
Prosecutors have said they believe no such organisation exists.
While the killer's credit card was used in London at the time, it is not clear he met with any fellow activists.
An EDL member who blogs under the name "lionheart" has previously denied meeting Breivik.
Breivik told the court on Tuesday said he "would do it all again because he was motivated by goodness, not evil."
During the trial he told the judge: "I do not recognise the Norwegian courts"
The far-right extremist said his bombing campaign and shooting spree was the "most sophisticated and spectacular political attack seen in Europe" since World War II.
The killer wipes away a tear as the court sees his propaganda video
As Breivik has admitted to the Oslo car bomb and shooting in Utoya, the trial is likely to focus on whether or not the killer is sane. His defence team have said the extremist would like to be found legally sane.