GoKawiilMarketing is almost always a tad disingenuous, and Analogue's FPGA-based recreation of the Nintendo 64 is no exception. Words matter, and while the Analogue 3D does indeed output 4K video, it's not magically turning retro games into native 4K creations. The console's HDMI signal can reach 3,840 x 2,160 pixels on a compatible TV, while most original N64 games were rendered at significantly lower resolutions, commonly around 320 x 240, with some reaching 640 x 480.
In terms of literal output resolution, the Analogue 3D is a 4K console, but it's not capable of adding detailed textures, geometry or animation that developers couldn't cram into a mid-90s cartridge. A modern remake of Super Mario 64 would be quite different, though the Analogue 3D is pretty good at eliminating the N64's famously blurry textures, distance fog and uneven frame rates. The console also does far more than your basic upscaling, and what it does do definitely separates it from the pack.
What Analogue is presenting is a faithful, better-looking version of the original experience for those of us ready to jump into our mental time machines and head back to an era of landmark hardware and couch co-op. Its 4K HDMI output and customizable Original Display Modes are designed to make games look crisp and clear on today's TVs. While its not reinventing the wheel, its much more than a standard emulator.