At one time, considering adding a character like Ego the Living Planet to a live-action comic book movie seemed absurd. Even with great special effects, the idea of a giant sentient planet facing off with heroes in space was not something anyone could assume would look right on the big screen. Even Galactus was changed to make the character fit into the expectations of a movie.
Things have changed drastically over the years. With Guardians of the Galaxy Vol. 2, James Gunn brought Ego to the big screen. He did it smartly, making the character look human for most of the movie, but even when Ego took his more natural form, it looked good. However, for everything that remained loyal to the comics, other things in Guardians of the Galaxy Vol. 2 had to change.
Accurate - A Living Planet
The biggest thing that made Ego a doubtful addition for any movie is one of the things that James Gunn kept in his film. While most of the runtime saw Ego as Kurt Russell, he was, in reality, a living planet. Ego only took the form of a humanoid to get what he needed in the grand scheme of things. However, as shown when the final battle started in Guardians of the Galaxy Vol. 2, Ego was a living planet and was almost impossible to beat.
Not - Peter Quill's Dad
In Guardians of the Galaxy Vol. 2, Ego the Living Planet was Peter Quill's dad. The film had him siring babies all over the universe to different mothers, trying to find the right combination to create a being with powers that could rule by his side. With Peter, he found that child. However, in the comics, Peter Quill's dad was J'son, an alien who was the rightful ruler of the Spartoi Empire. Ego had no relationship with Peter Quill in the comics.
Accurate - World Threatening Threat
As shown in Guardians of the Galaxy Vol. 2, Ego the Living Planet was a serious threat to humanity. The planet had some serious powers and could create life and destroy it just as easily. He showed how powerful he was when he wiped out the entire Sovereign military force sent out to kill the Guardians, almost effortlessly. In the comics, he is just as powerful and is a cosmic being that most heroes could only banish but never defeat.
Not - Took Human Form
In Guardians of the Galaxy Vol. 2, Ego the Living Planet took the form of a humanoid being, played by Kurt Russell. This was for one big reason. There is no way that Peter Quill (Chris Pratt) and the Guardians of the Galaxy could have developed a relationship with a planet.
In comics, it is easy to have someone like Thor flying around in space, talking to a giant planet. That would never work in the movies, so James Gunn took the best possible route. He made Ego look like a human.
Accurate - Has A Cerebral Core
When it came time for the Guardians of the Galaxy to take the fight to Ego, they had to find a weakness. It was classic Star Wars, where they found a weakness that they had to go inside the planet to find to take it out from within. This resulted in a giant exciting scene where they went into Ego and hit him where it hurts. In Marvel Comics, Ego the Living Planet also had a cerebral core, making that plot choice straight from the source.
Not - Traveled To Earth
The basis of Guardians of the Galaxy Vol. 2 has Ego the Living Planet took on a humanoid form and headed to Earth to find a woman he could mate with. This was important, as this was Peter Quill's mother, and she ended up having Ego's child. However, when it comes to Marvel Comics, he never did this, nor could he. There were moments that Ego tried to destroy the Earth, but he did it as a planet and not as an infiltrator on the planet itself.
Accurate - Psionic Powers
In Guardians of the Galaxy Vol. 2, Ego the Living Planet showed Peter Quill that they could do amazing things with their powers. Ego was able to manipulate energy and could shape and form it into anything. He could also use it to create light rays. He could also manipulate matter at a molecular level.
Ego has similar matter manipulation powers in the comics. He also has similar powers to the movie when it comes to his psionic powers. He can renew his energy storage by sucking energy from things close to him. This gives Ego, in film and comics, almost inexhaustible power.
Not - Ancient Celestial
Guardians of the Galaxy Vol. 2 seemed to be setting things up for the future, especially when setting up a movie like The Eternals. It did this when it chose to make Ego's race as a Celestial. As he said in the film, he is like a god, but not with a capital G. In Marvel Comics, Ego is not a Celestial. Instead, he was a scientist named Egros, who was turned into an ending planet by a cosmic being known as The Stranger.
Accurate - Its Atmosphere Is Alive
In both the Guardians of the Galaxy Vol. 2 and in the Marvel Comics, Ego is shown to be a fully functioning and glorious planet. His planet is full of life and is almost self-sufficient in the movie. There are trees, water, and it was beautiful when the Guardians were on it. This is the same as the comics, where he is a "bioverse," which means everything on its surface is alive as controlled by the consciousness of Ego.
Not - Comic's Version Is Insane
The Ego from Guardians of the Galaxy Vol. 2 was manipulative and had a strong plan. He set out across the universe and planted his seeds to create what he hoped would turn into his successor as a Celestial. He was not purely evil, but was self-serving and was out for himself. However, he was very different in the comic books. Ego was insane, unable to understand what he was doing most of the time. He had to deal with everyone from Galactus to Thor because they had to stop him before destroying everything.