Skills are whip combos that Leon (and Pumpkin in a @PUMPKIN game) can do to perform damaging attacks, or to provide a means of evasive actions .  Most of these skills can only be unlocked after certain conditions have been met, such as using a previous skill a given number of times, or after a certain enemy or number of enemies have been defeated, etc.  If anyone has info regarding this, feel free to email me; I'll add it & give credit.
ExtensionAdditional combo attack.
Draw UpDraws in lightweight
enemies for attack.
Vertical HighTosses enemies into the air
by slamming the ground.

Rising ShotAn upward attack
during a jump.

Fast RisingFirst attack becomes
Rising Shot.
then quickly 
Spinning BlastSlams whip energy into the
ground while spinning in a jump.

Energy BlastSlams whip energy into the
ground after a Rising Shot.

Sonic EdgeUnleashes sonic lashes
 in all directions.
Rotate left analog +
A Extension 1A midair combo attack
with the whip.
in midair
A Extension 2A more advanced
midair combo attack.

in midair
Step AttackAn attack during
a Quick Step.
During a Quick Step,
Falcon ClawA diving kick from
a double jump.
during a double jump
Quick StepMoves quickly in the direction of the
left analog stick to possibly avoid attacks.
Guard button +
Quick Step 2Takes Further evasive
action after a Quick Step.
During Quick Step,
guard +
Perfect GuardBlocks most enemy attacks
while gaining MP and hearts
Guard at impact.