So Arcade has been updated with three new songs, two from extend and the graphics have been changed slightly if you look at the video for Two Faced lovers: http://www.youtube.com/watch?v=0HU9bl-qp_g&feature=youtube_gdata_player
The "comic style" is only for Two-Faced Lovers because the PV is kinda comic-like with parts of typography.
Yup, the "comic style" is only effective for Ura-Omote Lovers because it is styled to suit the PV, which is comic-like, like what Hatsune said. Puzzle is a really beautiful song, it's only right for SEGA to include it now. Don't forget that "Luka Luka Night Fever" PV is also a Extend song and the PV is taken from Extend, so it is included as an Extend exclusive but not from the 1st Project Diva.