As of right now there aren’t too many things we know about Metroid Prime 4 other than the fact that the game is expected to be released exclusively for the Nintendo Switch most likely in 2018. In terms of which game engine that we are most likely to see for Metroid Prime 4 is something that has been debated in numerous gaming chat sites for a while now. When it comes down possibly game engines for Metroid Prime 4 a popular name that comes up is the Unreal Engine 4. Seeing a Metroid game on the Unreal Engine would be pretty cool for the Nintendo Switch.
However, there is always that possibility that Nintendo might give Metroid Prime 4 its own custom game engine similar to that of Super Mario Odyssey and Splatoon 2 which also came out for the Switch console this year. While utilizing the Unreal Engine for the upcoming Metroid game would be great its possible that Nintendo has other plans in terms of which game engine they plan on using.