Critics review shows on a per-episode basis, regardless if they are broadcast on a schedule or thrown out there all at once into the wild like Netflix/Amazon/etc. That's why critics panned it. I was watching it and evaluating it on a per-episode basis and more or less agreed with the critics' assessment. People watching it just queue up the next episode and it all just kinda blends together and smooths over the flaws you'd probably notice if Marco Polo aired weekly instead somewhere else.
edit: although the assessment that it being kung fu over historical drama is mostly a matter of taste. people have told me Marco Polo is supposed to emulate wuxia stuff from cinema over in China, which is supposed to be a blend of not-so-historical historical drama mixed with crazy over the top kung fu stunts (which I know I watched with the parents when I was younger), which might be the reason why.
edit: although the assessment that it being kung fu over historical drama is mostly a matter of taste. people have told me Marco Polo is supposed to emulate wuxia stuff from cinema over in China, which is supposed to be a blend of not-so-historical historical drama mixed with crazy over the top kung fu stunts (which I know I watched with the parents when I was younger), which might be the reason why.