Interesting situations :
Inception : the interwinned timelines of the dream levels, with characters having different challenges on different timings.
Matrix Revolution : the car chase on the highway, sometimes driving in the opposite direction. Jumping on and out of cars, fighting in the small space of a cab or on the top of a moving truck, the twins passing through car body.
Capes : a über-cool super-hero named Le Duc, with formal suit and cigar getd out of the car stopped in front of a residential house. "The kid, Aaron, he should be here", he says to his driver, looking at a paper with a picture and data. Then his enforcer, a three meters humanoid crashes the door open and enters the house. But the kid's mother, Miss Python, is already in the rear garden with him, and tries to escape with her serpentine agility. An omniscient man, Zimmermann, looks at the situation, reading Le Duc's thoughts to discover his agenda. But Le Duc, supernaturally nifty, shoots in the dark alley where Zimmermann believed to be unseen and seriously hurts him in the shoulder. Aware that the gunfire is attracting unwanted attention from the neighbours, Le Duc takes his cigar out of his mouth, blows the smoke and drops a bit of cinder. When it touches the ground, a spark emerges from it and runs to every lamp post around, shutting it off.
Scion : a scion of Artemis wearing leather and fighting with a scoped hunting rifle, named Selene, is running after a man. She begins to take vertical paths to get to him. She is so fast she seems to walk on the walls, and soon she is set up on the edge of a building roof, and sees the man through crosshairs. He doesn't see her anymore, and thinks he is safe, staggering from breathlessness. But then Selene's finger pull the trigger and in a loud crack, the head of the poor guy is spread on the wall behind him. Selene hook the rifle on her back, and jump from the building, slowly walking away.
Selfless (a game from the Reverse Engineering challenge on Story Games) : a man, kept in a psychiatric hospital, tries to remember his own name. The heartless doctor argues that he is named Sebastian, showing the records, but the depths of his mind, he knows that this is not right. Same that this is not friday but tuesday, contrary to what the assistants maintain. He has counted the days since his arrival. This is a big plot to make him really mad, so that they have a good reason to keep him.
Shock: : a mutant super-hero teenage girl with strong telekinetic powers hunts down some other mutants into the sewer. After several corridors and bends, she arrives in a big drain room, where dozens of mutants held hands in circle. And in the center, a skinny woman with empty eyes sockets who is levitating one meter above the water. She recognizes her mother.
Swashbucklers of the Seven Skies : the ship is boarded by savage men. A Kirin Gifted man, armed with a chain jumps from the high bridge on a rope, runs along it and leaps right in the middle of five savages. He swing his chain, teleports behind a savage who nearly hit him, knocks him out and rush to the next one. In twenty seconds, the five of them are unconscious and the man warps near the captain to protect him.
Tigres Volants (a french pulp science-fiction game, with elves, psis and dog-headed men) : the band organizes a huge improvised concert in an old hangar, gathering in it all the local population. They create a stage and plug their instruments in the outdated sockets. Then the rock music begins! The elf singer jumps into the audience and swims it. The electrokinesist keyboard player has the idea to add colours and sparkles to the show and starts using her psionic abilities. Long lighning bolts of red, blue and yellow electricity ride in the charged atmosphere. Finally, the fuse blows and all the hangar is silent several seconds, before the stampede begins.
I see it as a mix of dynamism (meaning either fast-paced or rich in outcomes), originality, emotionality, maybe skilled characters (or just active characters), with none being mandatory, and one being able to offset the lack of others by being very powerful. So that a very original but less emotional and dynamic scene is interesting, so is a strongly emotional but less original and without dynamism scene.
It's just a guess, because I've never seriously thought about that before.