I'm a big fan of 4A's Metro games, and I'm very much looking forward to the third chapter, Metro Exodus. But where 2033 and Last Light were sweaty, claustrophobic crawls through ruined, infested tunnels under Moscow, the new game, as this Game Informer report lays out, will be a very different sort of experience.
(And there are some slight spoilers in here, so consider yourselves warned.)
Exodus begins in the Metro but very quickly moves outside, beyond the city and into the snowy Russian wild. It's not a Fallout-style open world, however (something 4A has already said), but several large sandbox levels connected in a linear series of missions; side quests can be discovered and undertaken, but once you leave a level, you cannot return. The economy will be more akin to Fallout than in previous games, however, as ammo acting as currency is out and scavenging for things that can be turned into various useful items is in.
Combat and stealth have been improved to better accommodate the larger, more open levels, and instead of traveling between hub locations as in previous games, the hub will move with you in the form of the Aurora, the train that made such a dramatic entrance in the Metro Exodus announcement trailer at E3. There will also be standalone vehicles to tool around in, changes to factions and weapon upgrades, and even the game's time scale: 2033 and Last Light each unfolded over the course of a few days, but Exodus will cover an entire year.
There's an element of risk in walking away from a setting as distinct and recognizable as Metro's, but as much as I love roaming around in that hellish underground nightmare, the prospect of leaving it behind is exciting too. It's a bold step, and I really hope 4A can pull it off. Metro Exodus is expected to be out later this year.