There's meant to be a combo system, yet X360 was over two hours in before they unlocked the Achievement announcing they had chained their first combo, no matter how they varied their slashing and shooting patterns. This could have been caused partly by X-Blades' absolutely lunatic targeting system, which will only "lock on" to an enemy if it's directly in front of you. Casting a spell, however, will often move the camera and reset the reticule meaning you'll start hitting something else and usually get mullered by your original target, who will by now have recovered.
All this while you've got hordes of rampaging toothy things snapping round your ankles, draining your health away as you desperately try and work out what the hell to do next. There's really not a lot more to say – X360 doesn't recommend X-Blades even in the slightest. Just play Devil May Cry 4 again and save your money.