Many compare this game with Resident Evil, and I can see the resemblance in some of the mechanics: saves use ink, limited discrete inventory (each item takes one cell, be it a rifle or a pack of cigarettes), there are magic boxes to store equipment, and a lot of locked doors.
Combat system is different, though, with charge and stamina for melee weapons, and manual reload after each shot for firearms. You aim with your mouse, but there’s also a charge mechanic there, the reticle becomes smaller the longer you aim. There are also shooting enemies, something rare in original Resident Evil games for obvious reasons.
Story is very grounded. You are a French conscript fighting alongside your brother at Verdun. You are left behind in trenches now patrolled by Germans, and on the lookout for officers, scattered across the trenches in more than one sense, to get the keys for bunkers.
There’s a basic upgrade system, more of Resident Evil 4 than Resildent Evil 2, though, with generic stat boosts instead of custom parts.