In Avengers: Infinity War, the whole movie is a rising action, in a way.
You start with the quick but meaningful defeat of the strongest of the Avengers, the incredible Hulk. He fights Thanos, who defeats the Hulk with no help by using only his bare hands.
From there to the rest of the movie, the stakes are being presented and the villains start making their more assiduous advances to achieve what they want.
The rising action really builds up the stakes since Thanos becomes even more powerful and more unstoppable with every isolated victory.
The Climax is supposed to be the most intense, important or exciting point of something.
It came in the form of the final battle between Thanos and the Avengers.
To prevent Thanos from being able to destroy half of the universe, one of the main characters is obligated to kill her significant other, since he was only alive because of the Infinity Stone that Thanos wanted.
It was useless, since Thanos resurrected the poor soul by turning time back with the Time Stone that he had taken from Dr. Strange, only to kill the same guy and make the Scarlet Witch see him die again.
The conclusion was the victory of the bad guy, but the rising action was perfectly designed, battle after battle, to make Thanos seem more powerful and more dangerous.
At the same time, there was this side plot about the Ultimate Weapon that Thor was supposed to retrieve from the Dwarves. A weapon that was much, much stronger than his old hammer.
This also culminated to the climax since you go through this subplot with him and watch him fight with himself, grow as a character and deserve the Weapon that would save the Universe from the rising threat of Thanos, who felt like a real danger since he was killing the main characters one by one.
The final battle was epic and if felt like what it should be. The ultimate fight where all the stakes are high. In the Marvel Cinematic Universe, they had never been higher and since the main characters were dying, they never felt more real. I think we all felt like we were about to get our revenge when Thor seem to be winning the battle, and we all felt like the defeated heroes when Thor realized that he had lost. I know I did.
