What damoser is talking about is that it would look more authentic if the laughing man logo appeared as if it were composed from the individual code symbols, and NOT simply overlayed on top of some code like you have now. Compare your result with this picture to see what he means:
See how the pic of Neo is composed from the code symbols, and it is not just a pic of Neo overlayed on top of some code? Your laughing man logo has boundaries that leak in spaces where there is no code/text. That is the main difference. Therefore, it would be best to make the code under the logo to be the densest and brightest (like in the Neo pic), which contrasts from the falling code in the rest of the wall, and so it gives the illusion that the code is forming an image of the laughing man. damoser's masking technique is one way to do this. However, simply resorting to blending modes will not achieve this effect.
As for my critique, I'd say make the code under the logo denser and brighter (like how I said above). Also the code in the rest of the background looks too uniform - give it some more darker and/or empty areas to give contrast against the laughing man logo.