Thanks for your patience!
This case reminds me a lot of the second case I made as an author. It avoids a lot of the traps that new authors run into, it executes presentation very well, it has ambitious ideas, and the effort that went into this astounds me. However, the execution on those ambitious ideas isn't quite right, so the case doesn't deliver up to its full potential.
I will have more words to say about the bad because I think that as an author, you have a lot of potential, and working through the bad is the best way to get a case I can say I liked wholeheartedly. But first, let's talk about the good, because there are some very good things that deserve to be pointed out! I stand by that this case deserves much more attention than it has gotten to date.
First, I'd like to acknowledge the effort that went into the custom graphics. The chisel edit isn't trivial, and small details like changing the color of the various documents help to keep them straight. The edits to the crime scene also work very well. I can say from experience that was harder than it looked. I've always struggled with getting blood stains right and have a lot of respect for the edits.
You have down the basic idea of contradictions, which a lot of new authors struggle with: contradictions exist for a reason, and finding that reason drives the case forward, even if it takes a while for the true significance of the cross-examination to be found. I'm aware that the idea is not too complicated, but it's surprisingly easy to overlook, and I'm glad to see that you didn't fall into that.
The characters have distinct enough voices that I have a hard time mixing up their lines. Your defendant, Russel, doesn't sound like the detective, who doesn't sound like Justin Luther. Even better, the characters have their own motivations which affects their behavior. Luther is ashamed of himself for complying with Peterson, which causes him to be withdrawn until Apollo forces him to a fight. Russel is unusually uninvested in his own trial, which starts making much more sense when we realize that he's had death looming for a while now. I tend to focus on character second and case logic elements first, so I can't say that much here, but it still did the case many favors.
Two loosely related notes. One, the dialogue is mostly natural. (I feel it becomes less so when Peterson is discussed.) This is a lot harder to get right than most people think at first, and it's a job well done here! Second, there's an overarching story underneath all the murder. That was an afterthought for me when I first started, but overarching story is important to make cases feel like Ace Attorney as well.
Minor presentation aspects were mostly right, which removed quite a few distractions. Fades and the custom music selection were both very good ideas. There are a few grammar issues scattered throughout, but I can forgive those. Even things as simple as a background that changed during the introduction were enough to get me unusually invested in the case from the start.
This is more technical, but I'm also going to give this trial a great deal of credit for economy. It would have been really easy for you to create another witness to give the testimony about the defendant leaving and to leave Luther's cross-examination for when we wanted to follow-up on why the defense attorney did so badly that it looked like hw as trying to lose. That would have created another unneeded witness and just cluttered up the case. Instead, you made quite a lot of having him on the stand twice, which is exactly what I like to see! It gives some important clues for later and establishes a baseline characterization to make his personality change later on the more surprising and give more emotional weight to the actions of Peterson.
What truly astounded me was how ambitious this case was. Cases over 8000 frames are already exceptional. Cases that add in new mechanics and multiple crimes and overarching stories of this scale even moreso. That kind of creativity and commitment is encouraging to me to see. Now, ambition in a case has its bad side too. Trying to create an epic can make a case that's unwieldy when the execution of those ambitious ideas falters and things get longer and more complicated. That does afflict this case, as I discuss below.
There are things to finesse, but overall, you have a lot of the right ideas, and it comes out very well for the case!
Before I go on to the bad, I'll insert the disclaimer that reviews are inherently subjective. Not all feedback should be acted on, but feedback can reveal things you didn't even consider.
One, this mystery is very complicated. Even after having played this, I can't say how all the pieces fit together. When canon games introduce cases this complex, they normally have an investigation segment for the player to get the relevant information at a slow enough pace that they can absorb it all. I encourage you to replay whatever canon game you want as a point of comparison. Instead, this case adds complexity to complexity and includes frequent context shifts. Context shifts make it harder for players to piece together information.
For example, the first testimony is Ema talking about the HR-2 incident, Russel's motive, and the state of the crime scene. The second testimony is Luther talking about the timeline of the defendant and victim leaving the gallery during HR-2. Then we have have Fernando talking about the search for the victim and discovering the crime scene. This is followed by a fourth testimony from the defendant about his movements at the time of the crime and discovery of the crime scene. Throughout these cross-examinations, we're also learning about the yellow envelope, a note that Russel somehow passed from Carpenter, cryptic behavior from Klavier and the witnesses and the victim, and anonymous tips. I personally was bothered by the use of the masonry chisel, because I still don't understand why it was so imperative that the real crime scene be hidden. And this summary only covers around a third of the way through the case!
This was so much information to process that I couldn't hold it all at once. That the topic of conversation changes so much makes organizing information harder. Many contradictions and evidence presents, especially when Apollo is tasked to convince the judge to not declare a verdict yet, require the player to know the facts of the case extremely thoroughly. That includes not just the Court Record but fine details from several cross-examinations previous, with little prompting of what to look for. I just couldn't remember them all. If you want specific examples, I can give them to you.
I can't speak to what you were thinking during the design process, but the lesson I needed to learn when I made the same mistake was that making cases more complex, drawn-out, and intricate won't always make them more fun. When those cost the player's ability to follow along easily and sense of progress, the player just gets worn out. For me, this case crossed that line.
The last major part of "the bad" is a narrative point. I have a very hard time believing the story around Peterson. The cardinal rule with conspiracies is that the fewer people involved and the easier it is for them to play along with you, the better. For example, Manfred von Karma can get away with a lot of evidence forgery, but proving he forges evidence is incredibly hard, and there is nobody (that we know of) with enough information to expose him. Redd White can get away with tampering with the trial for Mia's murder, but the tampering he does isn't that hard. Nobody wants to go against Miles Edgeworth in the first place, especially for a client like Maya who can't pay. The prosecutor's office is happy as long as somebody goes to jail. Furthermore, Redd White only tries to extend his influence over people who are very safely under his control, like Marvin Grossberg. If he doesn't have something on you, then all he lets you know is that he's the CEO of Bluecorp, but you don't need to know what he actually does.
It's hard for me to believe the story about Peterson because he breaks both of these rules. First, the scale of his operation is massive. Just look at how Klavier talks about him:
"Orchestrating everything behind the scenes..."
"And continuing his destruction even as we speak..."
"He wanted to control the entire business scene... Be the top dog running everything... With unquestioned authority over the business world, he would run it with an iron fist..."
I can believe he would blackmail some businessmen, come out clean after some fraud investigations, have enemies killed, and even that he would place some bribes when he got into legal trouble. But running everything?
It's even worse because the things he's doing would get him caught very easily. According to Ethan, driving people to suicide is a hobby of his. Surely victims of that would be desperate enough to find somebody in authority who could investigate! What do they have to lose? That creates unwanted attention on Peterson, which should undermine his entire operation, no matter how "clever" he is. And what about "Many people found their wages slashed in half, maybe even by more... In fact, every company started doing this under the orders of this man... With less income, families began struggling to survive". This sounds like he is sending most of the nation into poverty. How on earth has he remained uncaught and unknown by the general public? You can place some bribes, but not even bribery would let you get away with crime on that scale.
Making things even less believable, it becomes very bad to be the person carrying out Peterson's orders. If you start ordering people en masse to commit serious crimes, such as halving wages and driving people to suicide, which is supposedly what Peterson orders fairly regularly, blackmail will not be enough to get people to follow along. Not with crimes like that. In comparison, Redd White just needs to tell people not to take a defense case they probably wouldn't want to take in the first place.
I understand that you want it to be clear that Peterson is a very very bad man, but you've more than made the point. It brings attention not to Peterson being bad, but to the fact that you the author are doing everything you can to make Peterson look bad. Again, I tried something similar in my second case, with a case that was far darker than it needed to be. You'll get a better sense of this with time, but it's important not to overdo "dark".