Alright, Kim asked me to elaborate the mechanics in Pokémon, to make it easier to compare.
First, you have the elemental types, of which there are seventeen. I'm not going to list them here, those of you who are interested know them anyway, and the rest of you don't give a damn. Any Pokémon can have a combination of two types, called dual typing (for example, Charizard is Fire and Flying). Moves only have one type, they are the same as the Pokémon typings, but a Pokémon can learn moves of more different types than its own. Moves which are "Super-effective" on one typing, will deal double the damage it would on a neutral typing, but moves that are "Not very effective" will only deal half the damage.
Please note the difference between type and typing. The first is used concerning moves, the second is used concerning the Pokémon. A full list of types is seen
here.
Dual typing is a double-edged sword. First, the benefits: If both typings are resistant to a certain attack type, the attack only deals a quarter of the original damage. We can go back to Charizard, whose typings both are resistant to Grass attacks. Now let's imagine him and Pikachu both being attacked by an enemy Bulbasaur's Razor Leaf (a moderately strong Grass type attack). The formula for damage calculation is rather complicated (it can be found
here). Let's for simplicity's sake pretend that both Pikachu and Charizard have the same amount of Special Defense points. Under normal conditions, they would be hit for an equal amount of Damage. But as both the Fire- and Flying-typings resist Grass attacks, while Electric doesn't, Charizard will only lose one fourth as much lives as Pikachu. These factors can also nullify each other. For example, the Fire typing is resistant to Ice attacks, while the Flying typing is weak to them. Thus, Charizard will take neutral damage from Ice attacks. On the other hand, if one of the typings are immune to a certain attack type, then it will override any weakness the other typing would have (Even though Ground moves are super-effective on Fire Pokémon, they won't hit Charizard because of his Flying typing).
Also, there is a factor called Same Type Attack Bonus, or STAB. In short, it means that if a Pokémon uses a move of its own typing, the damage done will be multiplied by 1.5. In short, if a Charizard and a Pikachu both use Fire Punch (note: In reality, Pikanchu can't learn this move) and they share the same Attack stat, Charizard's attack will be 50 % more powerful. Secondary typing also gives STAB, so Charizard's Flying attacks will be 50% more powerful than, say, Jigglypuff's.
Then, the drawbacks. You guessed one of them already: You get the weaknesses from both types as well. Both Fire and Flying are weak to Rock moves, and when combined, any Rock attack will do four times as much damage to Charizard as it would to Pikachu (see example above). Also, as seen with the Ice example, you can lose resistances if your Pokémon's secondary typing is weak to the attack type your primary typing is resistant to.
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Good. That was the basics. Then onto stats:
I've briefly mentioned the Attack and Defense stats above here. Pokémon have six primary stats, called Hitpoints (HP), Attack (Atk), Defense (Def), Special Attack (Sp.Atk or SpA), Special Defense (Sp. Def or SpD) and Speed (Spe).
The HP stat is the number of lives a Pokémon has.
The Attack stat determines the attack strength of a Pokémon's physical attacks (usually attacks where the Pokémon hits the opponent with a solid object). Previously, whether a move was considered physical or not was determined by its type, but it has later been changed, so that there are now both physical and special attacks of each type. A high Attack stat means the Pokémon will hit really hard, physically, but doesn't affect its special moves.
The Defense stat determines how well a Pokémon will take physical hits. A high Defense stat means that it will lose less HP when hit by a physical move, and can compensate for the opponent's high Attack stat.
The Sp. Atk stat determines the attack strength of a Pokémon's special attacks (damaging attacks not involving hitting the opponent with a solid object).
The Sp.Def stat determines how well a Pokémon will take Special hits.
The Speed stat determines which Pokémon will attack first. Yes, this is important. A high Speed stat means that the Pokémon almost always will attack first. Unlike the other stats, it's not important to have the highest possible Speed stat. As long as you're faster than the opponent, you should be satisfied.
There are ways to temporarily increase the Pokémon's stats (apart from the HP stat). More on that subject
here.
Each battle is divided into rounds. The trainers can choose between using one of the Pokémon's four attacks, switch to another Pokémon, use items, or flee. In professional battles, neither of the two latter options are available (well, fleeing means forfeiting). Again, which Pokémon attacks first in the round is determined by their Speed stats, but there are "priority moves", that strikes before any other move, regardless of Speed stat. If both Pokémon use a priority moves, the attack order will again be determined by their Speed stats. For a more comprehensible article on priority, follow this link:
http://www.smogon.com/dp/articles/move_priority
The battle is over when all Pokémon on one team is knocked out (have 0 HP left).
Then there are abilities. Each Pokémon has a more or less useful ability that may change the course of the battle.
Comprehensive explanation here.
There's also the effect of weather. About one in a hundred readers of this topic will even read this sentence, and less than half of them will have a look at the effects of weather
here.
And Items. Each Pokémon may hold an item that may change its performance.
Full list here.
At this point, I'd like to thank my eventual readers. If you have any questions about the game mechanics of Pokémon, hit me on MSN or drop me a PM.
Last, short about moves. There are about 450 moves in the Pokémon arsenal, ranging from useless (Splash) to absolutely devastating (Earthquake), of all types. All moves have three factors to determine their usefulness:
Base Power (how much damage the move will deal),
Accuracy (chance of hitting the opponent with it), and
Power Points (Or PP. How many times you may use the attack in the battle). Usually, a move will score well on two out of these three criteria and equally bad on the last (Splash, being the only move that doesn't do anything, has 45 PP and will never fail to execute, while Horn Drill, one of the moves that always will KO the opponent, has 5 PP and an accuracy of 30%). Of course, the moves can have other drawbacks as well, such as lowering stats or dealing damage to the Pokémon using the attack. Those effects can again be countered by using items or with abilities.
That should be it.