So an immediate caveat - this story contains many examples of yellow face and that is not acceptable through modern eyes - or indeed in general. This is not the worst example of it (mostly because time passed after this story) but it is worth noting. For this review I watched the Loose Cannon reconstruction and also listened to the soundtrack release - which is an interesting combination to get as full a picture as possible from a completely lost story with no official release.

I'm a fan of true historicals - and indeed in the first few series of Doctor Who I'd strongly argue that the best stories are the true historicals over the sci-fi elements that are often a lot more pondering. Marco Polo in particular stands out as unlike most stories its explicitly set over a fairly prolonged period of several months with big gaps in the middle as Marco Polo's retinue (including the Doctor, Ian, Barbara and Susan) passes from the Himalayas to Beijing. I think this is a big advantage - considering that we're fresh out of a trio of quite compressed opening stories and moving towards a different dynamic amongst the main cast (where the Doctor is more obviously one of the good guys, and not as morally ambiguous as the opening set of stories suggest) really helps that - there's an element of solidarity build up amongst the TARDIS crew at simply trying to escape.

While we cannot fully judge the visual elements of this story the tele snaps and photos make this look really impressive considering the budget of the show - and I think that's an element common with a lot of the early historicals (perhaps helped by being able to borrow more set pieces from other places). Of the missing stories its one of the ones that I most want to see video evidence of simply to see how the settings were conveyed on screen.

The story is also enjoyable - seven parters can drag and while this was not free from filler there was plenty here. The fact that the story moves locations a lot really helps this feel big - the desperation of the Doctor and others as they approach Shang-Tu where their chance to escape will vanish; Marco's increasing annoyance at his unexpected companions (and, somewhat notably, the first time that word is used to describe the Doctor's companions); and Tegana's schemes increasingly coming out - first appearing as a superstitious person before his real aim (representing Nogai against Kublai) becomes clear. The seven parts don't really drag in this - although there are a few moments where it feels like they filled screen time with either another failed escape in the TARDIS or Ian talking to Marco about them escaping. The climax works really well - Ian (imprisoned again after not convincing Ling-Tau of Tegana's intentions) manages to get Marco to intervene in Tegana's regicide attempt; and then Marco lets the Doctor, Ian, Barbara and Susan escape because of that act. It is very rushed and abrupt but I think works in the context of the story.

The disadvantages are the points where the script gets reductive with the 'escape get caught' stuff that Doctor Who at its worst is very bad at - although there are worse offenders here. Overall though this is a very fun story - and well worth seeking out.