HOW TO GET THE DELTA, EPSILON AND ZETA PART

To proceed in the Lost Gate you'll need 3 different "keys", here are the locations:

- 00:07 Remnant Wasteland, Extinct Civilization Depths

 

 

- 01:43 Solitary Sands, Lighthouse Midpoint

 

 

- 04:06 The Old South, Subway B

 

 

For a detailed walkthrough check the video below: