The first Ace Attorney game is a good start, even though you can tell that the writers were still trying to get a feel for the series.
The plot is good, showing Phoenix coming into his own as a lawyer and trying to save his old friend Edgeworth, which results in him solving a murder case from 15 years ago. Edgeworth is probably the most interesting prosecutor rival in the series, possessing a tragic past, a complex personality and a good redemption arc.
The story is surprisingly down-to-earth compared to the later games(with the possible exception of Apollo Justice: Ace Attorney), since the characters have less over-the-top personalities and simpler designs compared to later games. Whether this aspect is relatively boring or has its own charm is a matter of personal taste.
PW:AA establishes the gameplay AA is known for. In court, you press witnesses for more information and present evidence to find contradictions in their testimony, and outside, you speak with witnesses and search for evidence on the case. The investigation sequences are a bit tedious compared to those of later games due to lacking interactivity(e.g. the Magatama from the second game), but they're important to solving the mysteries and often involve surprising twists.
PW:AA's difficulty is reasonable, and has a simple but fair way of penalizing mistakes. Every time you present a wrong piece of evidence, you lose one of your five !s, and when you lose all five, the judge declares your client guilty. It keeps you on your toes, and is less arbitrary than some of the larger penalties in other games.
The first case is by far the simplest, easiest and shortest case in the series, since it can be finished in 20 minutes and has obvious contradictions(you don't even need to press the culprit).
The second case shakes things up and establishes the main plot of the game, although it suffers from a lackluster one-dimensional villain who would be completely obvious if the case wasn't a Reverse Whodunnit. It's not bad, per se, but it's probably the weakest case in PW:AA.
The third case is where the series starts Growing the Beard, with a more complex mystery, a less obvious killer and a few good twists. The main downside is that it's a bit drawn out and has some superfluous Fetch Quests.
The fourth case is probably the best, being an excellent climax to the game with a highly memorable villain and delving into Edgeworth's tragic backstory.
The fifth case, added in the DS release and later versions, is a good standalone case that has highly memorable characters, especially the culprit, and starts Edgeworth's redemption arc. While it's one of the longest cases in the series, it's well-written and challenging.
All in all, PW:AA is a solid experience that has overall strong gameplay and writing and few noticeable shortcomings. If you want to get into Ace Attorney, I recommend you start here.
EDITED: A good start to the series
The first Ace Attorney game is a good start, even though you can tell that the writers were still trying to get a feel for the series.
The plot is good, showing Phoenix coming into his own as a lawyer and trying to save his old friend Edgeworth, which results in him solving a murder case from 15 years ago. Edgeworth is probably the most interesting prosecutor rival in the series, possessing a tragic past, a complex personality and a good redemption arc.
The story is surprisingly down-to-earth compared to the later games(with the possible exception of Apollo Justice: Ace Attorney), since the characters have less over-the-top personalities and simpler designs compared to later games. Whether this aspect is relatively boring or has its own charm is a matter of personal taste.
PW:AA establishes the gameplay AA is known for. In court, you press witnesses for more information and present evidence to find contradictions in their testimony, and outside, you speak with witnesses and search for evidence on the case. The investigation sequences are a bit tedious compared to those of later games due to lacking interactivity(e.g. the Magatama from the second game), but they're important to solving the mysteries and often involve surprising twists.
PW:AA's difficulty is reasonable, and has a simple but fair way of penalizing mistakes. Every time you present a wrong piece of evidence, you lose one of your five !s, and when you lose all five, the judge declares your client guilty. It keeps you on your toes, and is less arbitrary than some of the larger penalties in other games.
The first case is by far the simplest, easiest and shortest case in the series, since it can be finished in 20 minutes and has obvious contradictions(you don't even need to press the culprit).
The second case shakes things up and establishes the main plot of the game, although it suffers from a lackluster one-dimensional villain who would be completely obvious if the case wasn't a Reverse Whodunnit. It's not bad, per se, but it's probably the weakest case in PW:AA.
The third case is where the series starts Growing the Beard, with a more complex mystery, a less obvious killer and a few good twists. The main downside is that it's a bit drawn out and has some superfluous Fetch Quests.
The fourth case is probably the best, being an excellent climax to the game with a highly memorable villain and delving into Edgeworth's tragic backstory.
The fifth case, added in the DS release and later versions, is a good standalone case that has highly memorable characters, especially the culprit, and starts Edgeworth's redemption arc. While it's one of the longest cases in the series, it's well-written and challenging.
All in all, PW:AA is a solid experience that has overall strong gameplay and writing and few noticeable shortcomings. If you want to get into Ace Attorney, I recommend you start here.