Summary
Pokémon Renegade Platinum is an enhancement hack of Pokémon Platinum Version, similar to my other hacks such as Sacred Gold & Storm Silver and Blaze Black & Volt White. In a nutshell, this hack generally keeps the same story flow as the original Pokémon Platinum but adds in a significant number of gameplay differences, including but not limited to access to all 493 Pokémon in the game, revamped Trainers including tougher boss fights, lots of (optional) changes to weaker Pokémon to make them easier to use, the removal of trade only evolutions and a number of other quality of life changes. The specifics of what parts have been changed are explained in the paragraphs below.
Features
All 493 Pokémon Available
All Pokémon that were originally in Platinum, from Bulbasaur to Arceus, are available to obtain within the game. The wild Pokémon for every single area have been modified extensively, now including species not ordinarily found in the Sinnoh region. It's possible to catch or obtain the majority of Pokémon before facing the Elite Four for the first time, meaning you can construct almost any team you want. In the cases where a Pokémon being in the wild would not be thematically appropriate - for example, starter Pokémon or legendaries - new events have been added to the game to make obtaining these Pokémon feel as unique as they normally would.
The details for where to get each Pokémon can be found between the wild Pokémon and special events documents. Additionally, the correct locations for wild Pokémon are also shown in the Pokédex. (Big thanks to Mikelan98 for that feature!)
Revamped Trainer Battles
The Pokémon rosters of every Trainer in the game has been edited, now including Pokémon from the National Dex. Trainer levels have also been modified to fit the new level curve, which is now higher than before due to bigger Pokémon rosters and greater use of evolved Pokémon awarding larger amounts of EXP. Trainers can now expect their Pokémon to reach the 70s by the Elite Four, instead of the 50s that was the case in the original Platinum. Additionally, all Trainers use the AI that is normally only used by boss Trainers such as the Elite Four.
The details for what each Trainer has can be seen in the Trainer Pokemon document. Please note that this feature is purely for the normal Trainer battles in the game; the Battle Frontier has not been changed.
Harder Boss Battles
Important battles such as the rival, Gym Leaders, Galactic Admins or the Elite Four have had their difficulty increased further than normal Trainers. Gym Leaders and Elite Four members now always use 6 Pokémon instead of the 3-5 from before, and all of these battles have them using high IV Pokémon with custom movesets, held items, and sometimes ideal natures. The first round Elite Four and the Champion also have the unique property of randomly picking from four teams to battle you with, making it impossible to know in advance what their lead Pokémon will be.
They shouldn't be literally impossible to beat, but are definitely a much greater challenge than the original version. You can expect some of your Pokémon to faint in battle unless you bring some strategies of your own to the table.
However, they do retain their aesthetics from the original, including their type focuses and signature Pokémon. Their signature Pokémon are also now equipped with a Poké Ball seal for some extra flair!
The details for all of these battles can be seen in the Trainer Pokémon file in the documentation.
Pokémon Modifications
The Fairy-type from the Gen 6 games and later has been added in Renegade Platinum, replacing what was previously the ??? type. All Pokémon have had their typing, base stats and wild held items updated to match what they are as of Ultra Sun and Ultra Moon, meaning you can now use Pokémon such as Clefairy and Ralts with their Fairy-type as in the later games. Pelipper and Torkoal also gain their new Drizzle and Drought abilities from Gen 7, and a lot of Pokémon gain their Hidden Ability from Gen 5 and later as a secondary standard ability in this hack.
All Pokémon have also had their level up move sets completely revamped. Pokémon will now learn their normal level up moves but now also learn other moves that enable them to be the best they can be, including TM moves, Egg moves and moves they only have access to in previous or later generations, up to and including Let's Go, Pikachu! and Let's Go, Eevee! Some Pokémon also get the chance to learn entirely new moves that they never could before, such as Megahorn for Pinsir and Earth Power for Typhlosion. The levels at which they learn the moves have been structured so that you can reliably access them just by naturally playing the game (i.e. you won't get moves at extremely high levels).
Some Pokémon have also had their TM/HM compatibility modified, in some cases adding in moves that they could ordinarily only learn in later generations (such as Drain Punch for Toxicroak), and other cases granting them access to entirely moves by TM (e.g. Drain Punch for Dusknoir). Additionally, several TMs have been replaced with new moves, including Scald, Wild Charge, Bug Buzz, Hyper Voice, Dazzling Gleam and Hurricane. Pokémon TM compatibility has been adjusted to match their compatibility in later generations, or in the case of the newcomers Bug Buzz and Hurricane, my best generous guess has been made as to what might be able to learn them. There's also been much greater compatibility added for Fly, meaning you don't necessarily almost always need a Flying-type Pokémon to get anywhere conveniently.
In addition to this, there are also a number of custom changes to make certain Pokémon unique and/or easier to use. Many Pokémon who are a bit weaker have received buffs to their base stats, meaning previously weak Pokémon like Butterfree and Ledian can now actually put up a fighting chance. Some Pokémon with decent stats in bad areas have had their stats reshuffled, such as Glaceon who is now faster but less defensive. Some Pokémon have also been given new types to play with, such as the now Bug and Dragon-type Flygon, or the Ghost and Fairy-type Mismagius. Some Pokémon also gain new abilities that they can't ordinarily get, such as Weavile gaining the Technician ability.
If you don't like the sort of changes that are listed in that last paragraph, there is an additional patch you can use called "ClassicVersion.xdelta" which will erase these changes from the game, leaving them the same as they would be as of Ultra Sun and Ultra Moon.