One thing that's almost immediately apparent in Baldur's Gate 3 is the quality of its character animations—it's hard to pick just one example, but Lae'zel's freaky little head jerks as she rants about the ghaik definitely come to mind for me. It turns out, the way Larian managed that level of animation detail was with a ludicrous amount of targeted motion capture of the game's many voice actors.
In an August 25 Twitter thread, Baldur's Gate 3 performance director Aliona Baranova explained that "All 248 actors, ALL the NPCs and not just the companions put on a mocap suit and their movements, gestures, and physical choices were recorded and sent along with the audio files."
Baranova does note that certain performances couldn't be paired with motion capture, such as more cinematic sequences or when the actor was unavailable. Ditto for the talking animals—I guess the real-life talking animals supplying the voices didn't want to get in those suits with all the dots on them, but I thought they were supposed to be professionals!
Baranova continued, "The iconic head wiggles [Jennifer English] did as Shadowheart WERE Jen's actual head wiggles. The militaristic and alien movements of Lae'zel were Devora Wilde's physical choice for the character."
Baranova describes the performance director role as working to "ensure that choices actors were making vocally matched what they were doing physically, and that this was clear when looking at the mocap."
That attention to craft certainly helped bring Baldur's Gate 3's winning main cast to life, but I'm just blown away that similar attention was paid to more minor NPCs. It helps avoid that gulf of quality between mainline content and side stories, and this aspect of Baldur's Gate 3's development is yet another indication that there was no "trick" to its success—just years of effort from professionals at the top of their game.