It's not input lag. The issue is a noticeable dead zone before Lara will actually move or aim. I've had to fight with it while using the pistol or bow, making headshots more difficult than they need to be. You get used to it, but still, it shouldn't be there.
The game looks gorgeous, and traversing the Siberian terrain has been very responsive and fluid so far. The challenge tombs are a huge improvement compared to the ones in TR 13. Do yourself a favor and switch off survivor's instinct. Makes exploration so much more enjoyable, as your eyes aren't assaulted with highlighted objects that detract you from enjoying the beautiful vistas.
Been rocking the TR 3 Antarctica outfit, which is definitely my favorite one out of the bunch so far. Pure nostalgia and the orange jacket and camouflaged pants provides a nice contrast to the icy terrain.
All in all, aside from the dead zone nuisance, I've been loving the game so far. Great port, Nixxes!