The German portal GameStar published a video comparing the graphics of the original Metro Exodus with graphics from the enhanced version. The original Metro Exodus was tested at maximum ray-traced graphics settings to compete with the Enhanced Edition.
Judging by the video, Metro Exodus Enhanced Edition has undergone a significant change. Thanks to the improved lighting system, some places are darker and more atmospheric, and some are lighter. Also in the Enhanced Edition, the quality of reflections has been significantly improved.
See the screenshots below:
Metro Exodus Enhanced Edition will release on May 6th on Steam, GOG and EGS. All owners of the original will receive this version for free. By the way Metro Exodus is also available on Linus and MacOS. See the system requirements for those systems here.