Brotato

To unlock this achievement, you'll want your weapons set to be entirely of Ghost weapons (Ghost Axe, Ghost Flint, and Ghost Scepter). They will boost up your damage, attack speed, and max HP by 1 for every set of enemies you kill with (Axe, Flint, and Scepter respectively). This will help with neutralizing the -100 damage output penalty you start with and building up your HP pool that will help you survive greater outputs of enemy punishment while also boosting your damage output for a given enemy wave. Have a weapons set of two of each as soon as you're able. Every time you level up, start bringing the damage rate from -100 until you get in the green, then prioritize building up your armor stat (which starts at +8) as well as dodge as damage output from enemies becomes bigger with each wave you clear. And also build up your life steal rate to complement the +20 HP regeneration default you start with.