I think people are taking out of context what was said in court, especially since it hasn't got to the point for him to make his final statement. He may be utterly wracked with guilt and self-loathing, I know I would. He only explained why he didn't, it doesn't justify it but it's the truth, he didn't take the pillow off because he wanted to get back to WoW. Nowhere does it say "It's really the games fault". He has to provide this information and it's relevant to the case. People on the internet get so irrational.
Back to point, I feel sorrow for the tragically early loss of life that occurred here, and for those close to the child in their time of mourning. This was irresponsible parenting in the extreme, and is indicative of an uneducated and immature approach to parenting. While he showed some forethought in making sure the child was secure, ignoring it's cries and generally not being in sight of the child at all times was callous and reprehensible. However, it sounds as though he will plead guilty to the charges, as he should, so this shouldn't be protracted. He will likely have lost everything important to him now, if that isn't torture he isn't human.
His lies don't make sense, I assume it's fear in face of losing his loved ones. Although to say his inaccurate depiction of his game time is a lie is a stretch, assuming he did find the child before she got home, he wouldn't have spared a moment to turn it off between weeping and having a break down. Or he might have just misjudged. The pillow lie was surely trying to save himself from looking utterly loathsomely negligent.
Edit: The murder theories I've read are quite disturbing, I hope for the sake of humanity it isn't true. Murdering an infant is unimaginably evil.