A man has been jailed for life for killing his former partner's 15-month-old daughter in Oldham.
Violet Mullen suffered "catastrophic internal injuries" in the weeks before her death, prosecutors said.
Gary Alcock, 28, was found guilty of murder and Claire Flanagan, 22, was convicted of causing or allowing her child's death.
At Manchester Crown Court, Alcock was told he must serve at least 21 years. Flanagan was jailed for five years.
Violet was punched, slapped and pinched by Alcock in the three weeks leading up to her death.
On 12 January, he delivered a fatal blow to her stomach which tore her internal organs.
He eventually dialled 999, telling emergency services Violet seemed "spaced out" and her lips were blue and cold.
When paramedics arrived at their home, on Huddersfield Road, they found she was not breathing and covered in bruises. She died shortly after in hospital.
Violet died from internal bleeding after suffering 35 separate injuries including multiple bruises, rib fractures and brain damage, which were comparable to injuries suffered in a car crash.
Flanagan was cleared of murder at Manchester Crown Court last month.
She was found guilty of causing or allowing the death of Violet by ignoring the obvious signs of abuse.
The court heard how she put her desperate need for a man in her life ahead of her daughter.
Judge Clement Goldstone QC, on sentencing, said: "In the three weeks before her death you, Gary Alcock, subjected her to repeated violence.
"This was the way you chose to cope with a demanding little girl who demanded your attention and interrupted your time-consuming hobby of playing computer games."
Alcock put Violet to bed on the day of her death, the judge said, "no doubt in the hope that you would have some time free to indulge your desire to play on your X-Box".
He said Flanagan knew for weeks that her boyfriend was hurting her daughter, but did nothing to protect her.
The judge told her: "As a mother you failed her miserably. That is something you will have to live with for the rest of your life."
Andrew O'Byrne QC, defending Flanagan, said she had been neglected as a child, in care by the age of 10, physically and sexually abused at home and pregnant at 16.
She denied any knowledge of the injuries inflicted on her daughter and said she would grieve for her forever.
Senior Investigating Officer in the case, Vinny Chadwick, said: "We are pleased that justice has been done for taking away a completely innocent life, and our thoughts remain with Violet's family, as they continue to come to terms with her death."
Councillor Jack Hulme, Oldham Council's cabinet member for children and families, said the authority was "deeply saddened" by Violet's death.
"Our objective now is to honour Violet's memory in the best way possible: by learning any lessons that might prevent other children suffering as she did," Mr Hulme said.
He said the Local Safeguarding Childrens' Board had carried out an independent review into the case and had submitted its report to OFSTED (Office for Standards in Education, Children's Services and Skills) for evaluation.