All characters come with three different skill trees which include a variety of enhancements ranging from simple stats improvements to actual abilities, abilities that make combat quite varied and much more fun. (wccftech.com)
The committee uses simple stats, but there tends to be at least a little correlation. (sbnation.com)
While sometimes you'll just get simple stat boosts, other times you'll be unlocking entirely different moves that add a new dynamic to the gameplay. (attackofthefanboy.com)