Vergil can cheat his way though the game because he dosen't use guns he is allowed to ttack with both the square and the regular triangle just press the both for easy style oints expecially is max power summon words.

Dante can weaken any boss by attacking it with the rocket laucher. In addition for cerberus use the shot gun on the leg to break all the ice in one shot and just attack it with the sword to make him stop also to avoid most attacks stand by next to the leg he sually attacks straight so it won't hit u as much unless he's red.