Horizon: Zero Dawn is a game that's been built from the ground up to take advantage of the PlayStation 4 Pro's additional processing power over the now-three-year-old PS4. That means that if you have a 4K TV -- especially one with HDR support -- it'll look amazing. Even if you have a normal 1080p telly, it'll look better than any other console you can buy.
Even on the far more common, lower-resolution 1080p TVs that most people still have, Horizon: Zero Dawn will still look better on a PS4 Pro. A graphics technique called supersampling -- rendering at 4K and then downscaling the output frames to 1080p -- takes care of any potential jaggies and aliasing on complicated in-game assets, particularly in the foliage -- always tricky for consoles and gaming PCs alike to recreate smoothly.
High dynamic range is even more important, we think, than 4K. HDR drastically extends the range of colour and contrast that a TV can display, and while studios can work with that huge gamut of extra information during development, it usually has to be heavily compressed into a small range of brightness and colour to display on a consumer TV. Because the PS4 Pro supports HDR output for games that optimise for it, you'll see a big difference.
Take a look at the gameplay footage above, recorded on a PS4 Pro at 4K at 60 frames per second. Down below are some screenshots we've downsampled to 1080p, but you can check out the full-res 4K shots on Sony's Flickr (warning: they're about 30MB each!). It's buttery smooth and looks gorgeous, even on your run-of-the-mill PC or smartphone screen. Think of how it'll look on a shiny new 65-inch 4K HDR telly. You're going to buy one with your PS4 Pro, right?