Just about all of them are 4K on PC.

I don't think you understand entirely what 4K gaming is. All the textures and visuals put into a game have nothing to do with the output resolution of a device. Yeah, it can make it more difficult to output a graphics-intensive game at 4K, but that's still on the device, not the game.

Angry Birds can be 4K just by outputting the game to the proper resolution, though in some respects it IS up to the developer how it will look in the end.

If you take an old game with 256x256 textures, you can still output the game to 4K, things just won't look as pretty (not that they would with textures like that on 1080p anyway)

There aren't "4K games" like there are 4K movies when it comes to PCs, and probably mobile since most devs don't keep a standard like consoles due to the crazy variety of screen resolutions available. 4K movies are that way just because there's the one disc that gets produced for a movie that has to conform to a standard.

You do realize that 4K is merely a standard resolution, and really doesn't require anything of developers to support, right?

In most game engines, resolution is just a variable that scales the rest of the game with it.

What that means is that once 4K devices start hitting the market in volume, they'll have a huge amount of retroactive support.

@Pandamobile
just because you can set it to 4k doesnt mean it is 4k quality.doesnt mean it can run it the way its supposed to.use an emulator to run a ps1 game at 8k maybe?so its the most advanced game in the world.?
half the video cards on the market barely run 4k videos properly. a few games like bf 4 and crysis barely meet the 4k standard and not more than a mere fraction of gaming pcs can do that at full speed

That doesn't answer my question, but thanks anyway....