You Can Take the Game out of the Metro, But...
While Exodus has been said to be the first open world game in the Metro series, that's not really the case. Of the game's five chapters, only two take place in 'open-ish' environments. These are the most prominent chapters, so about half of the game is open world(-ish) as opposed to 2/5ths.
The open world maps are decently satisfying to explore despite being apocalyptic-ally barren. Exodus borrows a lot of the better idea from Far Cry 2 here. You are also limited to three weapons at a time when out and about. Resources are thin and the only ammo types that can be crafted in the field are for the most unwieldy weapons, such as a pneumatic rifle that must be manually pumped like a super-soaker to maintain air pressure. Discovering and returning to safe houses from time to time is required to swap in different weapons and craft ammunition. You can also sleep at these safe houses in order to pass time. Like in Far Cry 2, the time of day can have advantages. Stealth against human enemies is easier when it's darker and they've consolidated themselves inside their bases, but also means micromanaging your flashlight's battery and so on. The open world maps are still fairly linear in terms of structure. Each one has a story path to follow in a precise order, there are very few sidequests to worry about, and even fewer points of genuine interest to discover.
The rest of the game is more of what you expect from Metro 2033 and Last Light: claustrophobic, linear dungeon crawls and spooky asset tours. This half of the game isn't necessarily bad, but certainly weaker than the open world and perhaps weaker than the claustrophobic dungeon crawls found in previous entries. That might simply be the measure of time speaking for me-- I've only played the games in this series sparingly over the course of about a decade, but even so its old bag of tricks has worn very thin. This game, both in structure and thematically, was meant to be a break from the Moscow metro systems of 2010, but too much of it feels stuck there.
But what truly drags the experience down is the storytelling. The underlying narrative is not at all bad, but it and its themes are conveyed in an extremely inelegant manner. You're constantly assaulted with unskippable story sequences where characters laboriously over-explain simple concepts such as 'where we're going next' and 'why.' There are also a handful of excruciating character scenes where you're meant to be charmed by the slices of life found among your journey across post apocalyptic Russia. Strupchek and Patyraj are getting married! Dravneyj is playing the guitar and singing a song! I understand and accept the intent behind these scenes, but the characters are so superficial that mining for depth, charm, and pathos is unwarranted. Especially UNSKIPPABLE mining that lasts about 10 minutes longer than it needs to for the point to be made. These story sequences are not well choreographed, either. Lines of dialogue consistently overlap each other like a Sonic Adventure 2 cutscene and characters just kind of stand around for most of them. There are also a number of agonizing sequences where you're accompanied on a mission by an NPC that moves at a snails pace.
I beat the previous two Metros on Ranger Hardcore mode, but I found that even Exodus's Normal difficulty errs on the side of aggravating. My attempts at playing in Ranger Hardcore just felt broken and off, so I gave up on it fairly quickly. I do not recommend playing any higher than Normal. Stealth mechanics are half-baked in a way that's stacked against the player-- it's the kind of game where enemies can see dead bodies and get alerted, but the player isn't allowed to move them and I never felt like the rules for being detected ever solidified into anything I could come to grips with. Success in stealth always seemed to come down to the player's ability to intuit the designer's intended path rather than any sort of cleverness or wit. Open combat is fine (on Normal; you're made of paper mache on Hard or Ranger) but really only succeeds in the open world where you have freedom to navigate the area. Unfortunately that's the exception rather than the rule. Most combat is done in tight spaces and oftentimes within scripted 'arena' sequences where bad guys keep spawning in, despite how little this complements the player's fragility and the overarching resource scarcity. Mutants are, as they always have been, a dull and obnoxious thing to deal with. I've hated them since Metro 2033 and they have not gotten better.
On one hand I'm delightfully surprised by Metro Exodus. The open world stuff didn't blow me away or anything, but it turned out better than I expected and it does not fall into 'the Ubisoft trap' as I had feared. On the other hand, I spent so much of the runtime being either frustrated-- or worse, bored by its half-baked indulgences.