While the Wii U version of Breath of the Wild has technically been running in CEMU since shortly after its release early last month, version 1.7.4c of the emulator ( released just yesterday to Patreon backers and to the public on April 9) fixes most of the outstanding graphical and gameplay issues that prevented the game from being fully playable through emulation.
Using the power of a Wii U emulator called CEMU, though, devoted coders have now got the game running at a full 4K resolution on a high-end PC. On standard Nintendo hardware, The Legend of Zelda: Breath of the Wild runs at a bare bones HD resolution of 720p, or up to 900p when using the Nintendo Switch in docked mode.
Be sure to take this video full screen and full resolution on a nice monitor to see just how good Breath of the Wild can look.