Greatsword - Greatsword Charge. You can charge the greatsword up to 3 levels. If you release the 3rd charge you will greatly increase the damage. There is also a new combo, after a downslash or unsheathed attack, you can tap x again and it will do a slap on the monster, which does K.O damage if hit on the head, then tap x again to do a greatsword charge. this charge does more damage than normal gs charge. By using the kick button, you can go from a kick, into a slap , into a gs charge.
You can search for the percentages on the attack when using the GS Charge, but this is basically whats new with the Greatsword.