Well... I did marathon the last few eps (10-24) and seriously, the series is not as sad as I thought it'd be. After watching the first few eps, i thought this would get into a sadistic frenzy, but it ended up being a great drama show with believable characters.
yea, we didn't end up knowing about the Masterminds or the battles, but in the end, that's how it'd be in real life. I personally find that the story is complete.

About the bread being the lifeforce... it didn't work like that. They always could fight for 48 hours. Ushiro was simply starving from fighting that long (like he would in other situations). The fight in front of the tower was also very long (where the tower was controlling the robot).

In the end... great show... i do recommend it. although, make sure you have time before you start the season... because stopping will be hard .