: Here's a comparison between the actual anime opening and the Halo'd version.
: For those who don't know, the premise is that all of humanity lives behind
: a wall that protects them from giant humanoids called Titans. Because
: their only weak spot is their neck, guns are almost useless and soldiers
: use swords and grappling-like devices, which let them fight in a vertical
: space.

: Comparison

Your description helped. I couldn't figure out the original creation either. I find Japanese anime difficult to follow sometimes.