We shouldn't need to know the answer to a question to determine if it should be closed.
I'm not a fan of any policy that requires you to know the answer to a question before you know whether or not the question is a dupe. And that's exactly what's happening here... a user needs to know that Counterstrike Game X and Counterstrike Game Y have identical answers to the question before he can know whether or not a dupe vote is appropriate. This bothers me.
What about remakes?
I was a little hesitant to weigh in on this issue because I think we get into kind of a weird area with remakes. The Secret of Monkey Island released in 1990. It re-released in 2009 with a few very, very minor gameplay changes and a very large graphical update. For 99.9% of the questions a person would have about the game, such as how to get past a given puzzle, the questions and answers will be identical.
Another example somewhere in the middle is the Spelunky HD version that came out recently. Some mechanics are exactly the same as the original. Some are totally different. In some cases, questions and answers might be exactly identical, in some the questions would be the same but the answers would be different, and in yet others the questions wouldn't even apply
Again, it comes down to a problem of users needing to know the answer before they can determine whether or not a close vote is appropriate. And again, the idea of using knowledge of the answer for close-criteria really, really bothers me. As silly as I think it would be to have a twin set of questions for Monkey Island and the remake, I think it's a better solution than trying to discern when a question and answer set are exactly the same and when there are differences. Realistically in those cases, the people playing are probably going to understand it's a remake and therefore very similar to the older version. They'll usually try out any answers they find to the old version before they ask about the new one.
So once in a while, we get some duplication that we feel could be collapsed into a single Q&A. How big of a deal is it, really, though? We don't even have to reproduce all the work in the case of identical questions and answers, right? If someone asks how X works in Monkey Island and gets a good answer, and someone asks how X works in the remake, a good answer to the second question might simply be to say "It works the same as the original" and then just link to the other question's answer, maybe adding a summary in there as you would with any good link answer.
Closing as a dupe turns close votes into super upvotes
Think about what we're really saying when we close a question as a dupe of an older game in the series (or the original version, in the case of a remake). We're saying "I know what the answer is, and it's the same as this other version. Do not argue with me about it... I'm right." Upvotes and downvotes should be the judge of an answer's quality and accuracy. We're effectively turning dupe votes into answers that can't be argued with.
- Intimate knowledge of the answer to a question should not be needed when determining whether or not to close something as a dupe.
- In the case where the answers are the same, a good answer can still help reduce duplication by pointing back at the original question and answer.
- In the primary use case of the site, people are often going google to find their answer on the older version of the question anyway. And if they aren't sure if it works the same in the new version, that's a question they should be able to get an answer to.
- Duplication really isn't that big a deal that we should be jumping through hoops to avoid it.