Two versions of the unstable mind of James Holmes were presented to a jury as lawyers revealed more about the gunman who opened fire on hundreds of moviegoers at a Batman premiere.

The lead prosecutor displayed an image of the cinema door on a TV screen as he told of a sinister but sane killer who methodically carried out the 2012 mass murder to make himself feel good and be remembered.

Public Defender Daniel King countered that Holmes suffers from schizophrenia, a diagnosis confirmed by 20 doctors.

Jurors must decide whether Holmes was able to know right from wrong when he slipped into the cinema, unleashed tear gas and killed 12 people and wounded 70.

He is charged with first-degree murder, attempted murder, an explosives offence and committing an act of violence for the mayhem he caused on July 20, 2012.

Holmes has pleaded not guilty by reason of insanity. His defence hopes jurors will agree and have him indefinitely committed to a mental institution. Under Colorado law, prosecutors must prove Holmes was sane in order to have him executed or spend the rest of his life in prison.