All the main Pokemon games starting from the first generation to the upcoming seventh generation feature the same RPG gameplay. You have Pokemon as your characters, travel from city to city, buy and sell items, talk to NPCs, and of course, battle other Pokemon – either through random wild encounters or trainer battles. Perhaps the only thing missing is a griping story that involves magic and other mystical and fantastical things. Battles, however, are a bit limited compared to a typical RPG. For one, you don’t have a Defend option. And as for offense, each Pokemon can only carry a maximum of four moves instead of the typical Attack, Skill, Magic or Summon that RPG characters employ.
The good news is that you can also have a maximum of six Pokemon, which totals to a possible 24 moves to use. But the bad news is that all these moves have limited use, especially the most powerful ones. Combine these limitations with Type strengths and weaknesses and you have a recipe for an in-depth competitive battling scene. However, Pokemon moves have been drastically changed in Pokemon GO, so your formidable knowledge of moves in the main games goes out the window. Everyone starts from scratch.
Things are more limited
Now, things have become even more limited than they already were. Instead of four moves for each of your Pokemon, you can only have a grand total of two moves – one weak-but-fast attack and one very powerful move. Every Pokemon goes by that rule. And even worse? You don’t get to choose which move your Pokemon will have. They’re set the moment you catch or hatch them, and they’re set the moment your Pokemon evolves. In the main games, moves can be acquired in different ways: leveling, breeding, using items called TM and HM, and going to Move Tutors.
This means even if you catch a Pokemon with a very high CP or perfect Individual Values (IVs), but it doesn’t have the moves you’re looking for, then you would be forced to abandon it. There’s no way around it, although you can save yourself the time if you buy a Pokemon with specific moves already at hand. The upside is that it’s now easier to predict what kinds moves a Pokemon might use compared to the main games. The absence of traditional Pokemon stats (Attack, Special Attack, Defense, etc.) and the lack of the Physical and Special distinction introduced in the fourth-gen games also makes battling less complicated.
An all-new battle system
Battling is more interactive now than simply choosing moves from a menu. As mentioned, there are two kinds of attacks: a Fast Attack and a Charge or Special attack. For the former, you simply tap on the screen. For the latter, you’re required to tap and then hold on the screen. Fast Attacks earn Energy every time you use them, which are then used to unleash a Special Attack. The faster you can drop Fast Attacks and the faster you fill up the Energy bar, the more chances you have of deploying the all-powerful attack.
But as always, things are not as straightforward as it seems. Different from the main games, the attack animation can’t be turned off – ever. This means that you have to go through every lengthy Solar Beam or Hyper Beam animation. Attack animations are factored into how much damage your Pokemon can actually churn out using a Fast Attack – commonly called as the Damage per Second or DPS. So, if your Pokemon’s Fast Attack has relatively more power but takes a few extra seconds to execute, it will be “less” powerful than a Fast Attack with less power but has faster animation.
The amount of Energy a Fast Attack earns is the least of your worries. For example, the Bubble attack is very powerful and grants a good chunk of Energy, but it also has a long animation at more than two seconds. This makes it “weaker” to Dragon Breath which has 1/4 the power of Bubble but only takes less than a second to finish its animation. It’s similar to the effect of cooldown times in League of Legends actually.
As for a Special Attack, you also have the Energy bar to worry about. Each Special Attack corresponds to a different 
type of Energy bar. Some have Energy bars that are broken down into two or more, which means that you can use that Special Attack two or more times before you need to charge Energy again. Some Energy bars don’t have partitions, meaning the Special Attack is a sort of one-time move only that depletes the entire bar. So for a Special Attack, you need to take into account its attack animation, Energy consumption, and power. As you can see, attack animations are much more important in Pokemon GO than in the main games where they’re simply a novelty.
Gym defense
When you leave your Pokemon to defend a Gym, you will have no control over it when someone tries to battle it. Everything is now left at the hands of the game A.I., which behaves differently than you do. The A.I. doesn’t spam its moves, especially the Fast Attack, like any sane player would in the heat of battle. There’s a two-second pause between Fast Attacks for an A.I-controlled Gym defender. But at least they use Special Attacks as soon as they’re ready.
This means that the aforementioned Bubble attack above would easily trump Dragon Breath thanks to the latter’s “forced” two-second charge-up time now. This means that your choice of moves depends on whether the Pokemon will be used as offense to dethrone Gym defenders, or as a Gym defender to thwart challengers. If the Pokemon is for offense, go with Fast Attacks that have very high DPS like Pound, Water Gun, Shadow Claw and Wing Attack. If the Pokemon is for defense, just go for the most powerful ones like Steel Wing, Rock Smash and Mud Slap.
You can check out all the in-depth details regarding all Pokemon moves in this Reddit page. And before you get too occupied with DPS and all these, remember that you still have Type strengths and weaknesses to consider.