v18 Gen 4 Battle Mechanically

[Abdoulgaming]

How can I resemble the Battle System as in the Official Gen 4 Games?

 

[TechSkylander1518]

Essentials is made to resemble Gen 5 IIRC, so the good news is you only need to compare those two! Bulbapedia's got a whole list here!

• Curse is a ??? move
• Rotom's alt forms are all Electric/Ghost
• Poison inflicts damage outside of battle
• Ninetales's EV yield was changed from 1 Special Attack and 1 Special Defense to 1 Special Defense and 1 Speed. Sky Forme Shaymin's was changed from 3 HP to 3 Speed
• During breeding, offspring now have an 80% chance to have the Ability slot corresponding to their mother, unless it is a Hidden Ability; for example, Venomoth with Shield Dust is more likely to breed Venonat with Compoundeyes than with Tinted Lens.

There is one other difference that would be tricky to go over, but I doubt anyone's gonna notice it:
"Many Pokémon have their experience yield changed, which is no longer limited to 255. Additionally, the experience formula now takes in account difference between Pokémon's levels."