The pc version requires a GTX960 to run. That card is 10 times larger as a phone. How is that possible?
Well, for one we know that hardware requirements don't usually align from one platform to another. This is the case even with PC and console, but I assume all the more so with PC and phone.
Also, despite cell phones having ridiculously high res for their size, that doesn't necessarily mean the games for them that have better graphics PLAY at that res. Quite frankly, the main reason phones have high res is to adapt the content to larger screens, especially since modern TVs are larger and more compatible with PCs and other devices.
And not to be ignored, frame rate, frame rate, frame rate! Anyone who's owned a console knows that a demanding game will usually be able to play at considerably higher FPS on a desktop vs a console. The latest gen consoles are no exception here.
Lastly, the bulk of the size of desktop GPUs, especially since custom designed coolers have been used on them, is the cooler itself. Those whom game on laptops and phones know full well they are NOT going to be getting anywhere near as good cooling, And this is also why laptop processors are often downclocked from their desktop variants.
So in short, you need to look at the big picture, even on a small device! One easy way to compare might be to run the game on your TV if you can get the phone to use it as a hotspot. On a larger screen it would be easier to see any of the shortcomings. What I mean by this is even on consoles, 1080p, or whatever you're running the game at, often doesn't look as sharp on console as on a desktop. This is because texture detail and LOD are often dumbed down for performance on consoles, and if not, the FPS, res, or both are adjusted on the fly to compensate.