Oh nice, thanks Mario ^^ Can you detail the different mechanics you're talking about?
One of them is the Field of Fonon (FoF) thing. When you use elemental artes in fights, you'll slowly build up a field of fonon for whichever element the artes you're using are; this is shown by some white rings being present on the battlefield. When the field of fonon is fully charged, it will turn a certain colour (red for fire, blue for water, brown for earth, green for wind, yellow for light, and purple for dark), different artes charge these at different rates (25% a pop, 50%, 100%).
In a field of fonon, particular artes can temporarily transform into entirely different ones when used whilst standing in one, but this only works if it's the right element. Light counts as fire and wind, whereas Dark counts as water and earth; these elements themselves are not required for any FoF arte changes, but they are helpful in activating some.
For example, the protagonist of the game has an arte called Fang Blade. If they stand in a Wind or Light element FoF and use it, then the arte becomes Lightning Tiger Blade and gains wind attributes at no extra TP cost. After activating a FoF arte for the first time, it is forever marked in your artes menu when you have its original arte selected, with the element you need displayed next to its name for future reference.
Another battle-related mechanic is the Fon Slot Chambers. As you progress through the game, you can come across these chamber items that can eventually be attached to your characters' artes to grant them bonus effects. For example, the Carmine (red) Chambers increase the potency of an arte (eg. more damage output, or a greater healing %).
The third one that comes to mind are Capacity Cores. Throughout the game starting from a certain point, you'll be able to equip your characters with one of these each, and they basically grant them a fixed amount of extra stat boosts per level up, which is essential for getting them AD Skills. AD Skills are like skills in other Tales games, but they require a certain amount of fixed stat boosts (the total fixed bonuses for each stat so far is displayed on the CC menu) to unlock each. There's no limit on how many skills you can have on, but you can turn them off if you don't want their benefits.
Not sure about anything else, haven't played the game in a few months. But any other questions, feel free to ask.