Thursday’s Lounge’s weekly Guitar Hero shred-fests are better than a lot of the local shows you’ve been to this month. Flipping between GH 1 and 2, Marilyn Manson disciples, college guys, longhairs, and rocker girls congregate, playing the addictive time killer on the bar’s seven-foot big screen, with the sound pumped through the club’s live-band P.A. system. The guitar might not be real, but the volume is.