DEFINITIVE SHOOTER OF THE 2010s. NO QUESTION.
This game was a pipe dream and a half to begin with, and then it actually came out and blew minds anyway.
Under the hood, You got this absolute barnburner of a 2011 shooter.
NOT EVEN USING UE4, USING A PROPRIETARY ENGINE, Relic delivered Gears of War style weight, camera-work, dazzling set pieces and cover-based sequences. From every step to every squeeze of your bolt gun trigger, (or every rev of your trusty chainsword) you FEEL it. As if that wasn't enough, the online matchmaking featured Halo Reach style armoury progression and customization, Call of Duty MW2 style loadout customization across 3 distinct player classes (tactical, jump assault, and heavy devastator), and on top of it all, its got a super schnazzy and stylized modern art style and story within the 40k universe.
This game set a very clear standard for how a Warhammer game should look and feel. Some REALLY unfortunate things happened for the publisher during and after this game's development and release, and any hopes for the proposed followup titles were all but dashed.
But over 10 years later, some licenses changed hands, some other companies were given the reigns to the franchise, some 40k lore was updated, the IP got a LOT more popular, and from completely out of left field, Saber Interactive took charge on completely revitalizing the title with an absolutely AMAZING sequel. which nowadays I would recommend to new players instead of the original, but even in its heyday, this game didn't get enough credit for what it did for the modern shooter in its era.