Destiny Damage Detail Introduction
There are four Damage Types so far that we know: Kinetic (white damage), this is what an ordinary weapon with no elemental properties deals, Solar (red damage) equivalent to fire damage, Arc (blue damage), comparable to lightning damage, and Void (purple damage) dark or gravity damage.
If you ever see an enemy that has a color aura around them like some Fallen Captain with a blue aura or Hive Wizards with a red aura, this is an indicator to switch to that damage type in order to easily break their shield. In other words, a Solar Damage type weapon or ability will deal extra damage to a Wizard's red aura shield, while an Arc Damage weapon or ability will deal more damage to a Captain's blue aura shield.
Each of the three playable characters from which we can choose have at least two subclasses that we know. The Titan starts with Arc damage class and his Subclass is Void damage. The Hunter's first class in Solar damage and moves to Arc damage in his Subclass. While the Warlock opens with a Void damage class and switches to Solar damage as a subclass. If you pay attention when you highlight your Subclass choice, their is a third slot that we don't know about. Speculation points to a third Subclass that would make sense for them to fill with the last Element that each playable character is missing. In other words, we are hoping for the Titan to get a Solar Subclass, the Hunter to get a Void Subclass, and the Warlock to get an Arc Subclass
All damage types seem to be capable of critical hits. These damage numbers will appear in yellow, as opposed to white, when you strike an enemy in a vulnerable area. If you finish an enemy with a critical hit it will result in a "precision kill" that may trigger some perks or abilities. Most enemies suffer critical damage when struck in the head. However, not all enemies have a traditional head and have different vulnerabilities. Spider tanks, for instance, are vulnerable on their legs at first, and when they collapse they reveal a vulnerable spot behind their head.