Al-Shabaab militants beheaded victims who could not recite passages from the Koran.
Witnesses said the masked killers laughed as they beheaded those who could not quote from the Muslim holy book.
Auma Geoffrey hid from the Somali attackers and heard Christians at Garissa University College crying for mercy.
"I came out and saw three of my colleagues beheaded bodies," he said in a Sun report.
"I'd heard the terrorist arguing with them because they tried to cheat the gunmen.
"But they got caught out as they were unable to recite Islamic verses."
Reuben Mwavita said that he witnessed three female students kneeling before the gunmen praying for help.
"The mistake they made was to say 'Jesus, please save us,' because that is when they were immediately shot," he told the Times.
Another survivor, Maureen Manyago said she heard one of the Al-Shabaab attackers say: "As long as Kenya's military is in Somalia, it will pay with its citizens' blood."
A father told of a final phone call from his daughter Salome Wainaina, an economics student. "Al-Shabaab is killing us," she said. "Goodbye. If we don't make it, I loved you all."
Kenya has announced a £175,000 reward for Mohammed Mohamud, who is believed to be the mastermind behind the attack at the Garissa University College campus, some 200km (120 miles) from the Somali border, in a pre-dawn rampage on Thursday.
On Saturday, Kenyan medical staff said they have found another survivor of the massacre.
Cynthia Charotich told Sky News from her hospital bed that she hid in a large cupboard, covering herself under a mound of clothes. She saved herself by refusing to come out when some of her classmates came out of hiding when shouted at by the gunmen.
Garissa University College is primarily Christian, reflecting Kenya's population which is 70% Christian and 6% are Muslim.