This game, sadly, is an unbridled meh.

I am in the process of finishing the 2nd map, not a great player for this kind of game so it takes me some time but the experience has just been mind numbingly boring.
Neither the story, the stealth mechanic, the action in combat or the environment excel in anyway and they all just oscillate between downright bad to mediocre.

The stealth, as the main component is repetitive, simplified and sloppy. The enemy patrol's LOS is a cone shaped light that starts a few centimeters in front of them rather than what I usually see in other games (originating from the npc) this means there is a HUGE blindspot gap left, right and center for you to exploit. Patrol routes and enemy allocation feels like it favors quantity over quality, in the sense that they rather sprinkle them around the map in large numbers rather than in making the effort to position them in challenging ways for the player's enjoyment.

This game also introduced hidey holes whose concept I find entirely silly for stealth games that have them but for some reason, the "dress-box" look alikes just feel extra odd for me in this game.

Environment wise, the first map which felt quite lengthy for me, for some unfathomable reason had most of it's chests empty and because there is a slight delay in the looting action and when the character tells you there is nothing inside, it just made looting an ordeal, this changed in map 2 but the design choice for the map 1 considerably damaged my enjoyment for the game.

I find myself comparing this game with few others I played that are as close to the genre that I can remember - Seven: The days long gone is vastly superior in story, mechanics etc. Mr.Shifty and similar action based games have less story than Seven but they also excel in proper action combat...Quantum Replica sadly, as mentioned in my first few lines, is mediocre at best in any category and downright trash in others.