I really enjoyed the series, but, I also played the video game. First, I'm absolutely thrilled how faithful they were to the source material. So much so that there were some scenes that were verbatim to the video game. It was refreshing to see a video game adaptation that wasn't butchered *cough* Halo *cough*. Second, the video game premise was actually more about the (without putting spoilers) story unfolding vs the outbreak. There was more focus on character development, relationships, and humans than there was of the "infected".
With all of that said, in the video game you did have to occasionally sneak through/fight off infected. I do feel like they skipped a lot of that in the tv series. It definitely seemed to be an after thought in the storytelling of the show. Felt like they just moved freely around the country without risk. I would have liked to have seen more encounters with the infected, but the lack of that didn't spoil the show for me. I could see how it could be disappointing for somebody new to the Last of Us lore, hopping in and expecting major zombie action, and receiving very little.