They did not capture the horror thriller or apocalyptic elements of the story that made their journey feel so dangerous. In the game they are pushed to the limits and that experience makes their bond so much stronger.

The danger, outside of the first clicker and the one swarm with the bloater, comes almost entirely from the other very few humans in the show. That is not in balance with the game. As a result Joel saving Ellie at the hospital didn’t have the same emotional effect the game had.