|P is for Practical|
Good article, just a few suggestions...
Your list of "fundamental Perl array operations" should be linked to the sections later in the node, like an index. See General-Purpose Linking.
In your "Clear an array" section, you don't mention this:
@array = ()
...but it does show up at the end of the section on splice.
At your quiz, you say "highlight text to see it", but then use a <spoiler> tag.
Your description of pop could be as detailed as your description of shift. Maybe put shift first and refer back to it.
I'm not sure "array slice" counts as jargon.
I think the whole section on splice would be better with examples. Showing equivalences to other operations such as shift is good, but those are available in the splice documentation that you link, and it might be nice if a novice could come learn about splice without reading everything else. The kind of examples I'm talking about are similar to what you write for unshift and friends.