Even though many things are kept alike, details like the story and game play have been improved, making a great sequel.
Throughout the game, you play as Apollo Justice. The main structure of the story is set in the courtroom where the judge sits 7 years older, still in action. You'll mainly be listening to a witness' testimony and cross-examining what was said. Pressing for details and presenting evidence to the court is what will mainly drive you forward. Unfortunately, much of that evidence will likely be provided through your trial and error. When you present evidence that makes sense to you, it won't in the game to Apollo, which will result in his stuttering, which results in a penalty. Too many penalties will result in a guilty verdict. To make this tougher, sometimes the penalty will double upon warning. Thankfully, that really only happens when the answer is obvious.
There are 4 episodes in the game, one of which is completely based in the courtroom. During the other episodes, you'll be outside the courtroom some, looking for evidence and people that may or will help your case. The outside world can bring some excitement, but it can feel limiting at times. If you aren't listening, you can miss major details that can make the difference of a few minutes or an hour.
The characters in the game are somewhat recycled, most of which are improved. For example, Phoenix Wright sure looks like a different person, not like an attorney, but like a casual fellow. Some characters though, like Ema, can really get on your nerve. Want something? You'll almost beg to get it. Some still have their humor or cool, but others are just the same.
All good things aside, there are still quite some problems. You can still get carried away with trial and error, but the problem is that you actually have to do it. You might present something that makes perfect sense, but Apollo will just act like a moron, and you'll receive a penalty. The mode where you can examine evidence also lacks any real reason to check it. Got a gun? The only information you'll really get out of it is Apollo's fear of where the bullet comes out.
The story is different, therefore it cannot be proven that it was improved. But that's not to say that it's bad. In Apollo Justice: Ace Attorney, everything is based on interest, or on the "Wow" factor. In other words, it's hard to stop listening to someone when they are explaining what happened. The end of the story also holds an interest that ties in a murder into Phoenix Wright's last defense.
When you put it all together, Apollo Justice: Ace Attorney feels no different than a Phoenix Wright. But the personality of it feels so intuitive that you cannot resist solving a few cases. Some points feel only like detective work, but all that aside, this game is easily recommendable to any fan of the law and/or courtroom happenings.