(1) If you came over tomorrow, we could play video games.
(2) If you had come over tomorrow, we could have played video games.
In general, you could use either (1) or (2) to express the idea, as long as there's enough context. But if you want to specifically emphasize there's a zero chance of the future event happening, you should go with (2).
The past tenses in (1) -- i.e., came and could -- represent a hypothetical world, which is different from a counterfactual world. It's possible that the former happens to coincide with the actual world, whereas the counterfactual world by definition cannot coincide with the actual world.
Therefore, if you use (1) it's entirely up to context whether there's any chance of the hypothetical future event of "you coming tomorrow and us playing video games". Thus, (1) is not the way to go if you'd like to emphasize the impossibility.
Now, let's assume your friend cannot sleep over at your place or visit your place two days in a row, and that for some reason you cannot play video games until tomorrow. But your friend just came over today, which means he cannot come over tomorrow.
In this scenario, there's a zero chance that your friend can come over tomorrow and you two can play video games together. And this impossibility arises from the event that your friend came over earlier today.
In order to describe the impossible hypothetical world in which your friend comes over tomorrow and you two can play video games, you need to look back at earlier today when your friend came over, which would require the perfect tenses (e.g., had come instead of came; have played instead of play) in both the if- and main clauses. Hence, (2).