The Planet Crafter

This achievement require you to unlock/create the last unlocked item in the game (unlocks at 360 GTi) and require a lot of grinding the late game items. I just focused on the T3 Tree Spreader. At around 59 GTi I began only focusing at rockets (each add 1000%) to the relevant items.

Then at around 120 GTi I began to simply AFK farm it. YOU WILL DIE, but dont worry, it dosent matter and you will automaticly respons in your base.