This looks fun, we should get it going again.
As far as the difficulty of the questions, what if we went with this approach? Either:
1. A somewhat obscure fact about a very well-known game or franchise
Or
2. A common fact about an obscure game or franchise
Having a very common fact about a well-known game often isn't satisfying(though fun sometimes), and wanting an obscure factoid for a niche game feels completely cryptic and unguessable to anyone not well-versed with the subject matter. Of course the difficulty is going to vary, but I'm assuming that's why participation has dried up. Looking through the thread, I've seen a pretty even mix of questions I either knew the answer to or could reasonably guess at, as well as hyper-specific things I could never in a million years randomly guess.
Of course, if you're not sure how approachable the questions are, multiple choice works well. Or, for a number-based question, how about whoever guesses closest gets it? Expecting someone to guess the exact numeric answer is kind of unrealistic unless there are only a handful of possibilities. Since we aren't expected to need to look up the answers to reasonably guess at them, it would help if they were at least somewhat approachable.
Then again, that's just my two cents, or three and a half cents after inflation.