As an animator, this is not that difficult to do at all actually once you have the right assets and camera angle. Helps that it's incredibly limited with it's movement. They use a lot of toon rigs for games like that, (ones specifically made for squash and stretch style animation) that are able to contort very easily, on top of just presumably loading in a completely new arm model specifically for that move and when you use the right perspective and the right poses you get a lot of good shots on top of the cellshading then you get animation like that. The timelapses in QB are incredibly well done, all that lighting data, effects, and assets loading and switching rapidly in realtime without any hits to performance is some magic type shit they even included weather:
Also still trying to find post mortems on how they did the facial animation in Mafia III, because wtf, because in a game this year.