The BDs for Symphogear (season one) came with three creditless versions of the OP (Synchrogazer). One difference between the second and third versions of the OP (I think the only difference, in fact) is that Yukine is added to this shot, which makes sense, since the third version of the OP is first used in episode 11, by which point Yukine is one of the "good guys".
But I cannot, for the life of me, tell what the difference between the first and second versions of the OP is. I even played them side-by-side, and still couldn't notice anything different between them. How do the first and second versions differ?