Sylvester Stallone plays various characters in Spy Kids. The main of them is the narrator of the Game and the rest are just his alter-egos. All right, we all know that Stallone is not very much of a character actor, so you wouldn't even expect some depth from his performance. The narrator is just there as a villain that only needs to be bad and in this particular case even funny sometimes.
He suceeded in being bad, as well as funny. The sad thing about it is that his acting is bad and he is funny not the way he was supposed to be. He is very very overacting and it's not as entertaining, as he intended it to be.
On the other hand I must give him some credits for enjoying this role. Though his performance just isn't technically good, it's obvious that he really liked what he was doing. And as I always keep saying: If an actor enjoys playing his part, so does the audience enjoy watching it. So there's one thing I must admit. Scenes with Stallone never were the ones that bored me.
What about his best scene? It's hard to choose one, because he is equally bad in his entire performance. But the final scene with an uncle might be played the best. And his worst scene is the scene, in which all of his character get the space. Here we can see how little he did for these character and how equal they all are. I mean, changing the accent and being masked isn't very much...