How complex would you define the rules of the "Yu-Gi-Oh!" card games, anime, etc.?

I have only played Magic the Gathering and compared to it “Yu-Gi-Oh!” rules that you provded and I find that it is very complex .

Yu-Gi-Oh was huge when I was in 6th grade and I remember finding the game hard to follow. I used to watch some kids play it and a few times I participated (I think they were just humoring me, letting me play, but I had fun). This just reminded me that I’ve completely forgotten how to play, but it was quite the burst of nostalgia :)

I’d like to propose a method to define the level of a game’s complexity.
The L C, Complexity Level, of a game is the square root of the number of pages in the instruction manual when printed on full sized paper using a font size of 11 – 13 pt. Fractional results shall be rounded to the next higher integer.
Using this method the L C of YuGiOh is 8.

I use a similar method to define the difficulty of a home repair. It is based upon the number of times you must visit the hardware store to complete the job.
A Level 1 job only requires 1 one trip to the store to complete.
A Level 5 job requires 5 trips back and forth to the store – once because the fitting is left handed and twice more because the unit is 50 years old and the housing broke while taking it apart. (Too specific?)

Well, I don’t do gaming, but everything with rules is complex until you learn it.

The card games in the show are like fight choreography. Looking flashy, but implausible in the real world.

It would depend on how many sets of cards you have and how well you know all of the powers of all of the cards. But if you have only one set, then all you have to understand is the powers of that one set.