What does "the heck" mean?

Does the meaning get any different when "just" is put before "here" compared to only "here" is used?

It is a little different! Here, "just" means "right" or "directly," and it adds a little more emphasis than just "here." Ex: The shop is just around the corner. => emphasizing that it's very close. = The shop is around the corner. => direct and monotone Ex: Look just under the table. => directly under the surface = Look under the table. => not as precise location

Just curious, does the expression "old-fashioned" imply a negative nuance?

"Old-fashioned" does usually imply something negative since it's out of date and no longer relevant. But it can just mean a vintage style, too. Here it's used to mean out of date since it doesn't use technology, but it doesn't necessarily mean that it's bad. Ex: I like old-fashioned stove tops. Ex: That way of thinking is so old-fashioned. Ex: I actually like old-fashioned dresses.

Can I replace "when talking about time" with "when we talk about time"?

Yes, you can replace "when talking about time" with "when we talk about time". Keep in mind that the nuance of each phrase is slightly different. "When talking about time" is a general statement that refers to anyone talking about time. While "when we talk about time" has the same meaning, the use of "we" makes this phrase sound more personal.

Is this sentence a present continuous tense? Is "are" skipped after the subject?

You're right, it is present continuous tense and the word "are" is skipped here after the subject in the sentence. In news announcements and article titles, it is common to skip lots of small filler words like articles and linking verbs, because they are already implied. Technically, it is not grammatically correct to leave these out, however, in English they are sometimes left out to shorten sentences since words like "are" are implied.

What does "stand-off" mean?

A "stand-off" is a situation in which neither of two opposing groups or forces will make a move until the other one does something, so nothing can happen until one of them gives way. Common synonyms for "stand-off" include "deadlock", "stalemate", and "impasse."