In Superman II, during the final battle between Superman, Zod, Ursa and Non (in the Fortress of Solitude), there was a part where they were disappearing and reappearing as false images (like holograms) to fool each other. Superman says to Lois that he used to play the game as a kid and that he never was very good at it. With whom did he play that would have had those powers? He came to Earth as an infant. Furthermore I don't buy that he was simply talking about hide and seek or some Earthly game. His statement that he was never good at it would not have made sense in that context.
The canon quote from the film transcript is
"We used to play this game at school. I never was very good at it!".
I think it's pretty clear that he's referring to 'hide and seek' rather than his newfound ability to make himself appear in multiple locations since that would have obviously have raised a very considerable number of questions. Furthermore, it's very likely that he's being ironic since his x-ray vision must have given him an incomparable advantage against his schoolmates.
In the original shooting script the line is slightly different;
"How do you like these odds, General ? Or are they too odd for you?"
closely followed by
"One more mistake like that and you'll be busted to Corporal, Zod.