Brotato

To make this achievement and many others easier from main menu go into options>Gameplay>Accessibility>Enemy Health/Speed/Damage down to 25% to make this game a lot easier

To win a run you will need to beat Wave 20 each wave has an increasing timer to survive waves of enemies to a max of 60 seconds, on wave 20 you will fight a boss after killing the boss and I hope that achievement appears right before you. :)