Early incarnations of TN were built around the time I was playing games like Reborn, Rejuvenation and Insurgence, and non-Pokemon games like Bloodborne. The game was initially balanced and designed with a grind-heavy, optimisation-requiring 'git gud' attitude. Enemies used extraordinarily powerful Pokemon, often feeling unfairly powerful.

More recently, this design has shifted. Focus is being put on making TN accessible and palatable to all users, from absolute die-hard grind-loving fanatics, to people who have never played Pokemon before. So TN is including multiple difficulty modes, which was probably going to be a thing even with the previous design philosophy, but the reasoning and explanation of those difficulties has changed.

I've experienced the frustration of a poorly designed difficulty, of picking Legendary in Halo 1 and getting my ass kicked, ultimately having to optimise the fun out of the game in order to proceed, or picking easier difficulties in metroidvanias and feeling totally unchallenged. So instead of throwing a first-time player into a screen basically asking them to blindly design part of the game themself, I'm planning clearly defined difficulties with explanations for which players they're for. Here's a run-down of expected difficulties and their target audience:

Normal: This is the recommended difficulty for most first-time players. Enemies use varied strategies, and often carry 4 Pokemon each. This difficulty is a noticeable step-up from official Pokemon games, and is more akin to fan-made games which often ratchet up the difficulty. Gym Leaders and other major opponents present a real threat and may defeat you multiple times before you work out a strategy to best them. Late-game, you will likely need to juggle 6 or more high-levelled Pokemon in order to counter the more challenging enemies. If you have never played a Pokemon fan-game before, you may be caught off guard by some fights. If you've never played Pokemon at all, you will likely struggle, and may lose to early fights many times before you learn the game mechanics. NPCs will explain the mechanics of combat to you if you ask them.

Hard: Not recommended for a first play-through unless you have experience not just with official games, but also with fan-games. This difficulty is comparable, though definitely lower than, games like Reborn and Rejuvenation. All major enemies carry full teams of 6, and may use healing items, and advanced strategies not seen in official games. You'll become very familiar with the Pokemon Centre in each town you visit, and will likely have to juggle 10 Pokemon by level 40, bringing out specific Pokemon to target certain enemies. This difficulty includes a level cap.

Very Hard: Not recommended for a first play-through. Beating TN on Hard before attempting this is recommended, but not required. This difficulty is roughly parable to that of the fan-games Reborn and Rejuvenation. Every single opponent, even the bug-catchers or low-ranking grunts in the introduction have a real chance of defeating you. Major enemies use full teams of well-trained, competitively-oriented Pokemon, sometimes at levels higher than your own Pokemon can reach due to a harsher level cap. This is far removed from the intended design and balance of the game, and your enjoyment of the game may suffer as a result.

Masochist: Not recommended at all. Nuzlocke rules are in place, and every single opponent has a real chance of ending your run. A combination of ridiculous skill, luck, determination and save-scumming will be necessary to beat this. This difficulty totally breaks the design of the game, and in playing this you will totally optimise out the fun of battling various miniboss opponents, and leave too long between story progression areas to actually enjoy the story. You should not play this difficulty, it exists only because a very small group of people would complain if it didn't.

Classic: This difficulty is similar to that of an official Pokemon game and is a very suitable introduction to both Pokemon fan games and Pokemon as a whole. Enemies can be beaten with wide ranges of strategies, allowing the player to use absolutely any Pokemon they like in any combination, with very little grinding throughout a playthrough. The early game can be beaten with a single Pokemon with little problem, but catching and using others is recommended as this will probably enhance your enjoyment of the game. This difficulty is guided at players who have no experience in Pokemon games, or would prefer to focus more on the story and spend less time training and battling than Normal difficulty intends.

Easy: This difficulty will not test your ability to battle Pokemon in any meaningful way. Some opponents are removed from the game, and those that remain use non-threatening Pokemon that pose little risk of knocking out your own Pokemon. This difficulty is intended for those with no experience with Pokemon battling who would still like to experience the battles in a more sheltered way, where mistakes are not severely punished. Playing this difficulty will allow you to use any Pokemon you like, in any combination, in any battle. You could decide that the Grass-type Cherrim is cute, and catch 6 of them and easily beat a Fire or Poison Gym. Whilst there is absolutely no shame in playing the game in Easy mode, this is far removed from the intended design of the game and your enjoyment will suffer. Normal mode (or at least Classic) is highly recommended, as Easy removes many carefully designed elements, including some dialogue that may have increased your immersion.

Story Mode: Almost every single battle is automatically won upon interacting with the opponent. This is intended for people with no interest in Pokemon, but who still want to experience the story-telling of Terra Nullius. A special NPC will follow you around and will explain things that you may not understand with no background knowledge, like that this Pokemon, Mewtwo, was created artificially as an attempt to clone this very rare Pokemon, Mew. This NPC does not exist canonically, no other NPCs will acknowledge their existence, and they are there simply to enhance your understanding of otherwise potentially confusing events. This is not the intended design of the game, and the pacing and weight of the game, and by extension your enjoyment, may suffer.