They reject apps for being too simple so meeting technical requirements is clearly not enough.
So, "Subjective reasons" such as? Example?
Here is an example of a 3D game running on the Apple Watch, that was approved by Apple, on the App Store, which looks rather "Quake like". Mindkeeper: The lurking fear (Apple Watch)[https://apps.apple.com/us/app/mindkeeper-the-lurking-fear/id...]