I use the following system to calculate the final score:
In each of the five categories (Story, Art, Sound, Character(s), Enjoyment), a score can get 2, 4, 8 or 10. 2 for something I find truly bad, 4 for something that just isn't good enough, 8 for fairly good and 10 for outstanding.

The sum of the score is divided by 5 and the score is rounded to the nearest integer (More than or equal to .5 rounds it up, less than .5 rounds it down).

STORY (2):
The story is very simple and very bad. A kid running around yelling about his mom being constipated? Yeah, great fun. I may be a bitter and old, but I remember childrens shows being better than this.

ART (2):
Crayon Shin-chan's typical style. As dreadful as always. Truly, this is an insult to many other childrens shows. Even though kids don't care that much about this particular area, can't they at least try to do something good? Blocky, uninspired art that has seemingly no effort put into it.

SOUND (8):
Nothing wrong with voices, sound effects or music. They do it all just fine.

Would've been a 2 if it hadn't been for the Den-O cast. Shin-chan is intolerable and annoying.

Not so strange, seeing how I'm a TAD too old to be watching this in the first place. Not that I'd show this to my nephews.

18 * 0.2 = 3.6, rounded up to 4.

I'm aware this is childrens show. I show my nephews (of mixed ages, the youngest one is 3 at the time of writing, the eldest is 7) various shows at times, this is not something I'd bother showing them. But if they enjoy either Crayon Shin-Chan or Den-O before this, sure, show them.