ANARCHY REIGNS

You get this for finishing all white MAIN missions on hard difficulty, you don't have to do all the FREE missions. If this is your first hard playthrough you will have to complete it as normal, prepare to swear, scream and shout.

However if you have already beat the game on hard on the black side you can do this:

1. Go to stage select

2. Complete White Red Side on hard difficulty

3. Complete white stage 4-3 on hard difficulty

4. Achievement will unlock on the medal screen.

There's actually a slightly faster way to get this, assuming you're planning to get all of the game's achievements.

1 - Play through the whole game on Hard starting with White or Black - you'll unlock all the hard level achievements, and one of the four ending achievements.
2 - Play through the whole game on Normal starting with the other colour - you'll unlock all the normal level achievements, and another of the four ending achievements.
3 - Now that you've beaten the game starting with both colours, every level on each side will be available to play on every difficulty. So just complete 4-3 and Red Side on the difficulty that you didn't the first time - for me it was white on hard and black on normal, and you'll quickly unlock the remaining two ending achievements.

if this is your first run on hard then you'll get it through it eventually (just be prepared for CPU's hurtful combos which almost kills you every time) but on your second run (need to have both Black and White side finished) instead of going through the WHOLE thing like you did the first time just start Black or White side on Hard when you beat the 4th chapter and you switch sides save and quit (or don't save i did just to be sure) go to stage select pick you're awesome Character pick last Red Side chapter you were on and finished no more havin to go through the WHOLE thing again (Hope this helps and good luck too ya)