OK just to chill you guys out, saying that "Ness= m2 but with zomg move".
Mewtwo is know for: Changing weather conditions(changing atoms vibrations), reading/moving/controling peoples mind/body, creating gravitational field(particles movement) and being able to teleport/create barriers, with the addition of having such a advanced brain structure it can actually changes reallity with his brain waves(particles movement and such).
Ness in the other hand is a kid that aqquired psyonic powers and can with those abilities "cast spells" and talk to things.
Ness never read anyones mind.
Ness never controled anyones body.
Ness was never proved to be abnormaly good with reflexes and such.
Ness attacks dont kill, just knock them out, mostly.
Ness is said to have the ultimate weapon, PK FLASH. A flash to actually cause some damage(besides blinding in eye contact), need to have ultra high temperatures, that in contact, or close to human flesh would melt it, thus making it a self destruction move.
The only way then pk flash is plausible is that a flash of light scares or knocks foes out by its brightness.
This is ness ultimate weapon, eyes closed and bam, it wont work.
Now onto body structure:
"Ness is a small child, with a big head. He is a average human, just with psyonic powers".
"Mewtwo was built by the world most advanced cientists to be a weapon, designed to change the world by playing with its physics, as moving particles and changing vibrations. The world is made of those, everything is atoms vibrating together, if you change how they vibrate or where they are, you can possibly kill anything or build anything. For that reasons, m2 was given abnormal analysing capacities, better than supercomputers, and a special spinal cord capable of doing so."
In game history: While mewtwo turned good in his movie, he is konw as the ultimate pokemon, and in the movie only resigned because people needed a happy ending. If you see, he didnt loose, he just turned good. Whereas, he fought lost of animals, pokemons, and changed world as we know.
Ness is a kid. He participates into a kid's game. In his journey he learns spells to kick peoples *** with hes powers, but most of the spells arent deadly, they dont kill, just knock them out. Flashes, dizzyness, headbuts, most of those dont kill, just injure or knock people out because of side effects. All of them wich can be countered by simple moves, such as closing eyes, or moving somes steps to the side, as they all come from a child.
In the battle: Ness dont have any tools to use. His only killing weapon is the stick, and melee moves, where he can teleport, or use psy moves to get free hits.
Mewtwo can predict and react to all those moves, plus, controling all the things he can, he can alterate anything around ness, or mess up with ness. Throwing him at rocks, exploding his head with pressure, toying with ness blood, you call it. Each one of those its a insta KO and dont take time to occur, basicaly instantaneously.
Add that to mind reading, and mewtwo can just act faster then ness or dodge any move he throws at him.
Ness is a kid, Mewtwo is a god, this is a unfair fight.
Next round please.