In this video guide I will show you how to defeat N. Gin with his Weapon of Mass Percussion. All you need to do is dodge the obstacles coming at you while looking for the little minions with flaming heads. Kill them to hurt N. Gin. There will be three stages of this while each one gets more difficult. As long as you get to the next stage, then die, you will spawn on the next stage. The last stage will require a bit of a pattern in order to save time and dying a lot. I would recommend staying on the right hand side and wait for the minion. Once he is defeated the achievement will pop.