The purple portal in Sell Lemons unlocks when you reach about 500 quadrillion investors ; once you hit that threshold, the portal appears and you can enter it to access evolution.

What to do

  1. Keep rebirthing to build investors.
  2. Watch for the purple Void Portal to appear in your base.
  3. Walk into it, then open the evolution menu.
  4. Evolve when your progress bar reaches 100%.

A couple of notes

  • Some guides describe the unlock as happening “around” 500 quadrillion investors, so the exact moment can feel a little delayed depending on your progression.
  • Entering the portal usually resets your tycoon progress, but it gives a permanent progression boost afterward.

Important detail

A few videos and guides mix up the game title as “Lemon Incremental Simulator,” but the unlock requirement they describe matches Sell Lemons and the purple Void Portal.

TL;DR: get to about 500 quadrillion investors , then the purple portal unlocks and lets you evolve.