Superman II Restored Internation Cut is something I've never heard of. Long story short: Richard Donner shot 70% of "Superman II" at the same time as "Superman" but the dumb powers-that-be wanted it to be more campy. So out goes Donner, in comes Richard Lester and we see a campier Superman II. And now someone has spent 4 years collecting and restoring the original footage. And here's the exhaustive different-shot-by-different-shot review.
And I really loved Superman II too. Wonder how I'll feel after I finish this review.