Powers are organized into a broader category called Power Sets.
Most Power Sets contain nine different variations of a particular power — but the key is that these variations aren't different in their overall effectiveness — just in how the player uses the power.
Take for instance Super Strength. As a Power Set, it has the following Powers:
A Punch is the basic Super Strength attack — it does damage, causes some knock back and is relatively quick to use.
Haymaker, however, does a lot more damage and knock back, but at the greater cost of endurance and time to use. A person couldn't hurl as many Haymakers in a given time period as he could Punches.
Both are useful powers, but in different situations. A Punch is good for taking on the relatively weak, but numerous foes players will encounter. Now Lieutenants, who boss around the minions, are a much different matter.
You'd need a couple of heroes/villains to work against those bad boys — and therefore, Haymaker might be much more appropriate in that situation.
But not all Super Strength powers are straightforward attacks — some are a little different. Taunt, for instance, attracts the attention of a targeted foe. Rage acts as a temporary Buff to a hero's damage resistance and damage.
Power Sets are quite varied in what they encompass.
The only thing that bounds what a Power Set can contain is the role that a particular Power Set is supposed to fulfill. Super Strength, for instance, is a melee attack power set. So is Claws, Martial Arts, Weapon Master, and Stone Mallet.
All of them are essentially powers that enable a hero or a villain to engage effectively in hand-to-hand.
Melee is only one role. The other roles are:
Every Power Set falls into one of these categories and Power Sets of the same category have the same general parameters. So Super Strength and Claws, which are both Melee Power Sets, are both devoted to hand-to-hand combat.
Their powers, however, aren't exactly the same; Claws, for instance, has a "Lunge" attack where the hero bounds to his target, while Super Strength has only those listed above.
At Character Creation, a person is able to choose a Primary Power Set and a Secondary Power Set — and the sets they are able to choose from are dependant upon their Archetype.
Tankers, for instance, have Defense power sets as their Primary Category and Melee power sets has their Secondary Category. This means that a Tanker's Defense powers will end up being more powerful overall than his Melee powers.
The player can choose a single Power Set from the Primary Category and a single Power Set from the Secondary Category. These will be the defining powers of the hero; they will have access to these Power Sets for their entire career. They are also the ONLY Power Sets that a player will have from his Primary and Secondary categories.
As a player gains more Security or Threat Levels, they'll have the option of choosing more and more powers out of each Power Set. The powers aren't all available immediately; these open up over time.