T.Nomura: Kingdom Hearts III on Switch “maybe” possible after the game’s initial launch

[Kowan]

Hiku said:

Mar1217 said:

KH3 runs on UE4. The Switch supports UE4. It's definitely gonna need some good tweaks to make it run well but it's not going to be a burden.

There's no magic UE4 slider that's going to make all UE4 games easy to port to Switch. A UE4 game can be created so that it is impossible to run on PS4 Pro beyond 1 frames per second if you so chose, no matter how you scale it. Example, you have 10 billion characters appear on screen at the same time.
It's not always a matter of scaling graphics. Removing entire assets is another factor, and that usually has to be done and compensated for manually, which is where most of the workload comes in.

If the game was created with Switch's hardware in mind, then the UE4 compatibility can make the conversion simple.
If it was not, then it may not be an easy task.

Exactly this.