The minor changes they made so far don't affect it. I would say they captured not just the look, but the feel of the game very well. It also seemed to move along pretty quickly, so I presume they will add more back story as flashbacks.
How Cordyceps spreads will be different in the show though, and they've essentially shown it already with the neighbor sequence. The Fedra sign also mentions only infection after a bite, more zombie like.