The gruesome assault came after the victim had been celebrating a birthday with two friends and when the bars closed, the group made their way into the village streets, while Broderick and Walsh walked about the town trying to initiate a fight with others.
About 3.50am the two teens approached their victim by the public toilets, trying to "antagonise and wind him up", while pestering him for a cigarette, before Broderick said: "I should just smack him over."
Walsh punched him in the head up to seven times, making his knuckles bleed.
Immediately after, Broderick and Walsh went to the Havelock North McDonald's where they bragged openly about the beating to several people.
CCTV footage from a nearby liquor store showed the two teens running from public toilets just moments after the assault.
The teens, who studied at St John's College together, eventually came forward following the publication of the video footage.
Judge Bridget Mackintosh said today that Broderick was a "talented sportsman" and had performed well at school, adding the attack appeared "out of character".
Broderick, who also attended Hastings Boys' High School, has been a Hawke's Bay junior cricket representative.
She said the attack was "probably fueled by alcohol" and described it as a "brain explosion".
Despite the electrician's family and friends later telling Hawke's Bay Today they were "disapointed and angry" with the apparent light sentence, Judge Mackintosh said the court sent a "stern message" and added people "need to feel safe when out having fun".
She gave Broderick credit for his "remorse" and "good character".
The vicitm's sister said she did not accept Broderick's remorse was genuine and said the "horrible attack" has left long-lasting scars for her brother and his family.
