Watchmen The End is Nigh Part 2

Full credit goes to minh2 from x360a for this. Beat the game to unlock Rorscach vs. Nite Owl mode, then load up a second controller to take control of Nite Owl so he can just stand there, then perform the combos in the following order:

YYXXXY (Maximum Damage)
YYXXY (Extra Damage)
XYYY (Fast Area Attack + Knock Down)
XXXX (Stun)
YXXYXY (Area Attack + Fast Stun + Fast Knock Down)

The achievement should unlock straight after, assuming you did all the above correctly and quickly.

After beating the game with one character, you will unlock Rorschach vs. Nite Owl mode. Set up a game using a dummy controller for Nite Owl. I recommend performing the eight Rorschach combos in the following order:

Extra Damage - Y Y X X Y
Stun - X X X X
Fast Stun - X Y X
Area Attack - Y X X Y
Fast Area Attack - X Y Y
Knockdown - Y Y Y
Fast Knockdown - Y X Y
Max Damage - Y Y X X X Y

The solution for Nite Owl's combos suggests that you may have to dashboard if you fail to complete this on your first try. I used the order shown above, and performed it on the first try. Nite Owl still had a slim bit of health left at the end, suggesting that you might be able to make a mistake along the way and still pull it off.

I included the names of the moves so you can tell if you pulled them off correctly, as they display on screen upon successful execution.

The Achievement should unlock after finishing the Max Damage move in the sequence above.