HBO's 'The Last of Us' is a faithful adaptation of the hit video game, but there are some key differences. Here's how they compare.

The biggest difference from the beginning of the game and the HBO series' first episode is at the very beginning. The show starts off with an interview with scientists on a talk show during the 1960s. One of the scientists warns that the most devastating pandemic would involve fungus that attacks the brain, eliciting disbelief from the audience.

This scene doesn't exist in the game, which begins with Sarah giving Joel a watch for his birthday.

The first episode of the HBO series then jumps to 2003 — and the watch scene — next. Like in the game, Sarah, played in the show by Nico Parker, gives Joel, played by Pedro Pascal, a watch. In the show, we see Sarah taking Joel's busted watch to a shop to get it fixed, and it's there she gets a sense that something is wrong, as the shop owner rushes her out.

Overall, the first episode spends more time with Sarah than the game does. We even see her spend time with her and Joel's neighbors, who only appear in the game when one of them attacks Joel and Sarah in their home after getting infected by the mutant fungus.

In the game, Joel is at work late and still gone in the middle of the night when Sarah wakes up. The player wanders the house as Sarah and can look at things like newspapers that foreshadow some sort of outbreak.

In the show, Joel puts Sarah to bed before having to leave the house to bail his brother Tommy, played by Gabriel Luna, out of jail.

But like in the game, Joel returns in time to save Sarah from their infected neighbor.

They pass a burning house where people they know lived, and the shot is almost identical to the moment in the game.

The HBO series adds an even more dramatic component to this moment: a plane crashes, sending their truck rolling.

Like in the game, Sarah is killed in the show by a soldier who is given orders to kill her and Joel out of fear that they're infected.

Just as in the game, Tommy arrives in time to save Joel — but is too late to save Sarah, who dies in Joel's arms.

Like in the game, Joel is now in Boston, doing what he can to survive with his partner Tess, played by Anna Torv. The show focuses more on Joel's desperation to leave the quarantine zone and find his brother Tommy than the game does at the same point in the narrative.

In the game, Tess kills Robert. But in the show, he's already dead when they find him, having been killed in a shootout with the rebel group the Fireflies.

When they find Robert's body in the show, Joel and Tess are confronted by the local leader of the Fireflies, Marlene, played by Merle Dandrige, who also voiced the character in the game. She promises to give Joel and Tess their supplies back, including a truck for them to escape, if they can smuggle a girl named Ellie, played by Bella Ramsey, out of the quarantine zone.

Joel is incentivized by the promise of a working truck, as he wants to find Tommy, who he says he lost communication with in recent weeks.

In both the game and show, Ellie has been infected, but hasn't turned into one of the deadly "clickers" weeks after being bitten, suggesting that she is immune and could be the key to a vaccine.

Ellie tells Joel that his "watch is broken" in the show, just as she does in the game. Joel still wears the watch that Sarah gave her, even though it is shattered.

In both the show and game, Joel, Tess, and Ellie are confronted by a soldier who Ellie stabs — only after he is able to determine that she is infected. Ellie explains to Joel and Ellie that her bite is weeks old.

The episode ends with Joel, Ellie, and Tess making their way out of the quarantine zone to take Ellie to a group of Fireflies in exchange for the truck and supplies.