Gon aside since nothing changed for Gon but his body and the maximum limits, so he just powered up what he already had, Netero's laser attack was totally different from the slapping the buddha statue was doing up until that point. I find it quite hard to believe Netero wouldn't have practiced that attack before when he was developing it. He might have put more power into it this time, but he was a very old man in any case.
Said by the foremost expert in nen: A few months old ant. You know, Gon himself knows many times more about nen than Pitou ever did.