It's similar to how old games look so different on modern hardware: the pixel art on a current-day screen looks like high-fidelity perfectly sharp uniformly colored squares, while the "pixel art" of old games rendered on a CRT didn't look like "pixel art" at all but rather like high-fidelity art rendered on a low-fidelity screen. There's a lot of detail implied by the way CRTs render what's encoded in software as perfect squares.