To get this achievement, exclusive V Special or Perfect, you need to finish the game with one of the bosses: Amakusa, Zankuro, Gaoh or Mizuki.

To do so, you'll have to beat each one of them using a special move called "Overkill" (fatality).

*There is information there are 2 moves you can use. But here just what I got, which is Overkill

To do this special move, use the buttons below

- The hit is done in 2 steps and with conditions

.Conditions:
...have won 1 round
...have the weapon
...the opponent's bar is blue

The move:
1 - First you will have to change the scenario, to stay with Rage Explosion
This is done with directional, punch, kick and the special button (special button is one he doesn't hit)







2 - With the different scenario you can overkill, note that the opponent can defend himself. To let you know you've done it, you'll unlock an achievement called "A bit much". There's blood in case you were doubt.
You'll have as much time as you can to overkill, don't need as soon scenario changes. But only can do once.
The buttons: directional, kick and special

Video for you to know how it is