It is now over a decade since Western Australia enacted in 2008 a discrete homicide offence to address deaths resulting from so-called "one-punch" assaults. Four other jurisdictions subsequently introduced similar laws: the Northern Territory in 2012 and in 2014, New South Wales, Queensland and Victoria. More than a decade on, it is timely to examine the operation of these laws in practice. This article examines 53 cases finalised during 2008–2018. It highlights six features that may be regarded as unintended consequences or otherwise at odds with the original justifications for their introduction: impact on the prosecution of fatal domestic violence; impact on Indigenous offenders; net widening effects from "classic" one-punch public alcohol-fuelled violence; effect of statutory alterations to common law principles; effects on charging, pleas and alternative verdicts; and sentencing outcomes.