My best so far was the Pink Floyd song Echoes, hardcore mode, 1.8 million. And I only made it 14 minutes of the 23 minute long song. Its not that its an intense song either, quite the opposite, so lots of time with the pea shooter, including at least one of the 3 bosses at that point.
It was on normal, so it wasn't too bad difficulty wise, aside from a few close calls and the fact that I was down to 1 life like 30 minutes into the song, but man, that was one hell of an endurance test. --- http://i40.tinypic.com/2pydfub.jpg http://i40.tinypic.com/2nhnuys.gif