Even though Metro already was one of my favorite series and I was quite sure I'd enjoy this one a lot, Exodus surpassed my expectations, keeping everything I liked before while making additions to the design that improved the formula. Thrilling, emotional, eerie, gorgeous... without a doubt one of the best games I've ever played.
Combining the previous close quarters, mostly underground and very linear maps with bigger, more open, exterior areas was a great and perfectly executed idea. They managed to create levels that incorporated some of the fun parts of a sandbox game but, even during those sections that gave more freedom to move around and explore at your own pace, it still was a very guided experience that kept the focus on the story and setting, which are the things I most loved about the earlier entries and was afraid could suffer if they went too far in the open-world direction.
The art design was amazing, full of beautiful but very creepy at times environments, the combat was tight and tense and it was one of the very few games that really made me care about the characters and their tribulations. Thanks to its stunning visuals, solid gameplay and top notch narrative I was completely invested in this extraordinary journey from start to finish.
More info: https://en.wikipedia.org/wiki/Metro_Exodus