Dog eat Dog makes WAY MORE SENSE being sinister but I had never before actually successfully been given the feelings of sinister-ness from the song before. It's a hard line they're trying to walk with the Thenardiers being both the comic relief AND the villains.

I agree, though, that the movie does a good job with that -- I too though it was excellently done to include a cheerful wee!Eponine in all of it as a sort of reminder that what's going on is Not Okay.