Titles should be straight forward and in the form of a question. Your suggestion:
What game is this from? (probably an old Japanese arcade platformer)
There are two problems here. First, "probably" should not be in the title. What if it's wrong? So the whole phrase should go.
Even without the probably, this still isn't in the form of a question: ...
A proper image-less experience would show you the actual text of the buttons, as you can see by looking at the source of the page. For example the upvote button should show the "up vote" text as the source reveals:
title="This question shows research effort;
it is useful and clear (click again to undo)">
I believe this is due to the fact that some of those tags can include wildcards or not be real tags at all, so it is simpler to not attempt showing an excerpt overlay at all.
Plus clicking on each tag has two possible outcomes: either taking you to the full tag page or removing the tag from your favourites (if you click on the X).