Yes and no.
In general the game's UI should be custom-tailored to the game rather than using generic platform-wide styles that don't really fit in. For example, most of the modern minimalistic styles seek to look futuristic and sleek. Hence, they would feel really out of place in games set in the middle ages where the purpose is to look and feel old, not modern. Likewise, with retro games the smooth, curvy, and thin UI elements of Material Design would feel out of place with all of the pixelated and clunky graphics elements of the game.
However, those all focus on the style of the UI elements and not their layout and function. You should still try to have your UI fit in as far as layout and function goes. For example, Material Design dictates that the primary action of an app should be in the bottom right corner, usually in the shape of a colorful button. And likewise you should try to follow that where it is applicable. For example, you could have an in-game store and the primary button might be to view your inventory.
The UI should be tailor-made to suit the game itself, but you should always try to follow some conventions as far as layout goes to make your app easy to use.