What is then narrative style used in "The Veldt"?
The style is allegorical and suspenseful, making use of foreshadowing.
A neutral third person omniscient narrator tells the story. The Hadleys live in an expensive “Happylife Home,” a technological marvel that is fully automated. One of the features is a huge nursery that is controlled by the children, where they can make it look like anything they want.
When Lydia tells her husband George that there is something wrong with the nursery and she wants a psychologist to look at it, this foreshadows that something is wrong with the children.
The parents seem to think that technology is going to raise their children. They spoil them with things and then leave them alone. Neither one really wants to get involved.
"I'm afraid." She came to him and put her body against him and cried steadily. "Did you see? Did you feel? It's too real."
"You've got to tell Wendy and Peter not to read any more on Africa."
"Of course - of course." He patted her.
When the psychologist arrives, he tells the parents that the violence demonstrated in the nursery is dangerous.
This is very bad. My advice to you is to have the whole damn room torn down and your children brought to me every day during the next year for treatment."
They still don’t listen, and soon the children kill them. This is a cautionary tale about spoiling and ignoring your children, but also about letting technology have free reign over your life.