The game is setup in a way in which you are always underleveled compared to the Gym Leaders. (If you think grinding can help, GL with that. The wild Pokemon are probably 5-10 levels under you at that point)
In addition to this, the Gym Leader A.I.s have been upgraded a whole lot compared to normal trainers to the point where it is not uncommon to lose your first match and require switching out members of your party due to Gym Leader having an attack you unexpectedly did not see coming
Features of these games include
Custom sprites/mapping Fakemon New regions (starting with Vega) Custom OST (starting with Vega) New attacks Somewhat questionable new evolution paths for existing official mons.