A Pokémon battle is a form of competition between Pokémon. In these battles, one or more of the Pokémon is typically owned and trained by a Pokémon Trainer, in order to win.
Interface of Battle Screen
Selecting "Fight" will bring up another menu which allows the player to choose which of his or her Pokémon's current moves is to be used during the turn. Depending on its remaining PP, a move may or may not be able to be selected; at least 1 PP is required to select the move.
Once both sides have selected the moves they will use, the Pokémon currently in battle will make each of their moves in turn, with the Pokémon with the highest Speed stat going first, and the one with the lowest Speed stat going last. Depending on the moves used, items held by individual Pokémon, and status ailments, this progression may be altered, with moves like Quick Attack having an increased priority.
As each Pokémon makes its move, a Pokémon may faint if its HP reaches 0. If this occurs, another Pokémon must be switched in to replace it in battle for the battle to continue. This switch occurs before the turn ends.
If "Bag" is selected, it will bring up the contents of the player's Bag on screen. If an item is selected to be used, this will take place before any Pokémon makes its move, and the player's Pokémon will not be able to make a move. The Bag selection is sometimes disabled, most notably in Matchmaking.
Selecting "Pokémon" will bring up a menu of the player's current party Pokémon, allowing them to be checked by the player or switched into battle, sending the player's active Pokémon back into its Poké Ball.
If "Run" is selected, the player will attempt to escape from the battle. Battles against NPC Trainers cannot be run from. This option, like Fight, also depends on the Speed of the Pokémon in battle, with a calculation made based on the two resulting in either the player escaping a wild battle (if the player's Pokémon's Speed is high enough) or being stuck in battle and losing a turn. Trapping moves and abilities can prevent escape attempts from being made, as can the player's own Pokémon if it has previously used Ingrain.
PvE, otherwise known as Person vs Environment can either be a Pokémon Trainer vs NPC (Non-Player Character) or Pokémon Trainer vs a Wild Pokémon. From these types of battles are players only able to earn experience points for their Pokémon.
Players vs Wild Pokémon can be found at any patch of tall grass across the Kanto region. The level of Wild Pokemon found through Kanto range from 2 (Route 1) thru 68 (Cerulean Cave).
Players vs NPCs are often battled as well because of the money they can give out. Players can earn both money and experience points by battling NPCs. This can be done over and over again when using the Key Item, VS Seeker. The VS Seeker has a 100 step cool-down and every trainer can be re-battled at ever 6 hours of real time. NPC trainers range from having at least 1 Pokémon to having 6 in their party.
PvP, otherwise known as Person vs Person is two human trainers against each other. With the new Matchmaking system, found in any upstairs Pokémon Center, players can wait in a queue to battle another player across the region, no matter what channel they are in.
A Double Battle is initiated when two Pokémon, rather than one, are sent out per side. Double Battles can alter a player's strategy by a lot, now having to evade twice the moves and make twice the decisions per turn.
Several moves change when used in Double Battles. While most will target one of the two Pokémon, selectable after the move itself is chosen, some target both opponent Pokémon, both opponents and the partner, the user and its partner, or all Pokémon in the battle. Abilities may have an effect in Double Battles that is very nearly useless in Single Battles, such as Plus, which requires another Pokémon in play to activate.
Tag Battles are two players vs two players. Currently, this is not implemented yet.