With Abby's first day beginning, the second season has finally come to an end. Like the previous episodes, the final episode still made a lot of changes to the original plot, bringing more confusion to the audience...
1.The series modifies the triangular relationship between Ellie, Jesse, and Tina.
At the beginning of this episode, Jesse heals Tina in the theater. After guessing that Tina is pregnant, he has a conflict with Ellie. These plots are not present in the game.
In the game, there is no depiction of a romantic relationship between Jesse and Tina. Only at the beginning, when Tina shows concern upon finding Jesse injured, it makes Ellie a little jealous. And Jesse himself truly respects and blesses Ellie and Tina as a couple.

2.Modifications to Jesse's character setup.
In the series, Jesse is highly expected by the people around him and is being groomed as the next leader of Jackson. He also delivers a speech about responsibility to Ellie. These plots are not in the game; Jesse is just a good buddy of Ellie.
3.Ellie knows Abby's story.
In the comparison of the fifth episode, I mentioned that during her days in Seattle, Ellie had no idea why Abby killed Joel. She always thought Abby was just some Firefly seeking revenge. But in the series, Ellie clearly knows that Joel killed Abby's father and tells Tina about it in this episode.

4.Modifications to Abby's character setup.
This episode originally creates a plot where Isaac, the leader of the WLF, plans to invade the Scars' headquarters in the camp. It mentions that Isaac is grooming Abby as the next leader of the WLF. However, in the game, it is only mentioned that Abby is Isaac's "top enforcer", similar to a special forces member with some privileges but far from being a successor.
This may be due to the physical build of the actress playing Abby, changing her from a strength-based character to a leader-type one.

5.Ellie has no sympathy for the Scars.
In the series, while Ellie and Jesse are on their way to find Tommy, they encounter a group of WLF members torturing Scars members. Ellie indignantly steps forward to try to take them down. But in the game, Ellie shows almost no mercy to the Scars... (Tina's arrow wound was in vain)
6.The series modifies the scene where Ellie and Jesse argue.
In the series, Ellie and Jesse have a fierce argument about whether to rescue Tommy. There is a similar segment in the game, but the means of expression is completely different.
First, in the game, Ellie is at the edge of a mental breakdown by this point, with only the thought of killing Abby in her mind, thus conflicting with Jesse. But they don't have a fierce quarrel. Jesse just forces a smile and leaves, because he realizes that Ellie has completely fallen into the abyss of revenge and lost her rationality.

In addition, Ellie never says something like "Joel is her community". Because in the game, Ellie's motivation for revenge is very complex. It's not just because Abby killed Joel, but there are deeper psychological motives. Besides, from her character setup, Ellie's long-cherished wish is to sacrifice herself to make a vaccine, so it's unlikely for her to say such a thing.
7.Ellie has never been to the Scars' island.
On the way to the aquarium, Ellie's boat is overturned by huge waves, and she is stranded on the Scars' headquarters island. Later, she is almost killed by the Scars. This is a completely original plot of the series; in the game, Ellie never goes to this island. The series may design this segment as a gimmick for the third season, but the final effect is a bit strange...
In the game, Ellie is swept into the water by huge waves on her way to the aquarium and then directly swims all the way to the aquarium.

8.Mel is not accidentally killed by Ellie.
At the end of the series, Owen, Mel, and Ellie confront each other. During the counterattack, Ellie accidentally kills Mel.
In the game, Mel is not accidentally killed by Ellie; Ellie kills her with a knife intentionally. However, she doesn't realize that Mel is pregnant at that time. Later, Ellie falls into extreme shock and guilt, even vomiting on the spot, which completely shakes her will to revenge.

In addition, there may be a potential loophole in the series. In the game, Ellie takes out her own map (on which the theater is marked as her base) and asks Owen to identify it. Later, in a panic, she leaves the map in the aquarium, which allows Abby to find Ellie.
But in the series, Ellie asks Owen to identify his own map, which obviously has no clues related to Ellie. So it's unknown how Abby finally finds her way to the theater in the series. It may be explained in the third season.