You can change the difficulty anytime you want. Difficulty determines how tough your opponent is, not just story mode but also multiplayer mode as well.
- Easy: Your opponent is dumb down, giving you an easier time to pummel your opponent.
- Normal: Your opponent is well balanced. Not too easy, not too hard.
- Hard: Your opponent is a madman! Not only do you really need to strike a lot, you have to grapple and defend from all kinds of attacks!
In story mode, the difficulty also determines how much attributes you earn as you build up your fighter. Here are your stats:
- Upper strength: This affects your punching power and grappling strength.
- Lower strength: Your kicking power can help your through the fight.
- Speed: This helps your move faster and attack quicker.
- Defense: It's important to uphold their attacks by countering and blocking attacks.
- Health: You really need this to survive as your life is on the line.
Charisma is not listed after the prequel. You need huge amount of cash to make your charisma effective. Think like this: No one likes an ugly duckling. Try to buy expensive clothes, jewellery and tattoos in your budget range and it will become a beautiful swan (sounds familiar?). Overtime, the crowd that's behind you will also grow.
Even though you can max your stats through normal and hard when you combine three styles, if your doing it on easy, you better stick to two because of the lower attributes. Nevertheless, you can change the difficulty anytime but that would be easily confusing using that kind of method.