A flag and a coat of arms are two completely separate things. A coat of arms does not belong on a national flag and shows a misunderstanding of how a national flag should be designed. A coat of arms is too complicated to be on a flag. The first nations to be knocked out are…
As with coats of arms, a flag should not feature another flag. This is a feature of coats of arms.
Although Tonga technically doesn't have another flag on it, it appears to have the flag of the Red Cross in canton. It just looks like it's a sub-division of a health organisation, not a nation. Taiwan has the flag of a poltical party in canton.
A map and a flag are two different things. Don't confuse them.
Writing has no place on a flag. This is not an advert or a religious text.
You may not be able to see it but Brunei has a couple of sentences in small writing.
Honourable mention: I will be lamenting the knock out of flags that had potential. But the rules must apply to all. The flag of Brazil starts off well: the green field; the yellow diamond and blue circle, very striking. But then just falls down massively. The stars are way too complicated and it's the only national flag in the world to have Latin words.
All elements of a flag must be easily identifiable and, just as important, easily reproducable with some fidelity. These flags fail in that.
See the page on colour for more explanation, but basically this is about how a charge (the object) needs to contrast well with the field (background).
Honourable mentions: Kenya and St. Kitts & Nevis both work well. But the shield on Kenya is getting a bit pictorial, and they would both have been eliminated in round 9.
This is about contrast, where a field has multiple divisions but uses no white or yellow.
Fibriation is just a border around an object, as opposed to a border around the whole field.
This is about contrast, where a field has multiple divisions but uses no white or yellow.
Honourable mentions: Nepal is a very distinctive flag because it has unique shape, but it's odd in many ways – the shape, the top charge, the border. South Africa also is distinctive, but not classic. Trinidad & Tobago is classic, but it's charge is slightly odd (not exactly corner to corner) and it's fimbriated.
Not just charges that overlap, but odd charges.
Angola has machete overlapping half a cog. Half? Bosnia has nine and two half stars. Two halves? And an oddly positioned and oddly orientated triangle. Kyrgyzstan has the crown of a yurt overlapping the sun. This flag gets an honourable mention. Initially it looks great, but on closer inspection is too complicated. Oman has a sword overlapping a sword overlapping a dagger.
Just plain odd.
Liechtenstein's flag has a crown. Again, something this complex belongs on a coat of arms not a flag. Malta has a medal on its flag. Something that belong on your chest, not your flag. Nauru looks like it has put its sun under the water, not really sure why. Rwanda has put its sun opposite the hoist side of the flag. That would be OK if there was something in the hoist, but it's empty.
Honourable mention: Greece
Pairs of flags which are, or effectively are, identical.
Probably the most controversial round, but there's just nothing going on. Just a simple field division, in two or three, and nothing else. Dull. Doesn't say anything.
Honourable mention: For me the one that sticks out in this bunch is Germany.
The worst colour to use in a flag, as the flag should be seen against a blue sky.
While an animal is a good thing to have on a coat of arms, a flag needs to be reproducable. Animals and plants often have no standard way of being reproduced, or if they do, it is quite complicated. There shouldn't be the need to send an EPS file to everyone who wants to make the national flag
This is the last knockout round. These flags are slightly too complicated – a certain number of stars, or a rule that they should be a certain way up, neither of which could not be ascertained if they were at the top of a flag pole.
Honourable mention: United Kingdom is a classic flag, but has that weird assymetry to the red saltire. It's unnecessary.