The Gospel of Judas, I assume your talking about, is a gnostic text. Probably wasn't actually written by him, but it is clearly a self edifying text. Whereas the other texts tend to focus on Christ, his focuses all on Judas.
Luke 22:3...........
"Then Satan entered into Judas called Iscariot, who was of the number of the twelve."
1 John 2:19........
"They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, in order that it might be shown that they all are not of us".
I agree with your comments on Judas's gospel. Other than the title of the document, there is no evidence it was written by Judas Iscariot or that it contains any legitimate historical information. It appears to be a second-century Gnostic pseudepigraphal (-spurious writings, especially writings falsely attributed to biblical characters or times.) gospel.