Did they change companies? It all seems pretty different. The colouring is less detailed and overall more saturated, there's a lot less texture, including facial contouring that was part of the character models, and some stuff that looked believable now looks like body paint. On the other hand the movement is more continuous where S1 had mostly still shots punctuated by quick movements, and the computer models look mostly the same.
Sorry if this has been covered before.