What are the implications of the word "Nofeil"?
Rashi #1 (citing Targum Onkelos): It implies that Hashem appeared to Bil'am ("u'Gelui Einayim") at night-time when he was lying down in bed.
Rashi: Because he was uncircumcised and it was disgusting for him to stand upright before Hashem when He revealed Himself to him. See also Ba'al ha'Turim.
Targum Yonasan (on Pasuk 3): Because he was not circumcised he fell on his face until the angel (conveying the prophecy) had finished. (It is not clear however, why Targum Yonasan mentions this in the previous Pasuk and not here?
And what is the meaning of "G'luy Einayim"?
Targum Onkelos: Refer to 24:4:1:1.
Targum Yonasan: Deep secrets that were hidden from other prophets were revealed to him.