Following Nintendo's E3 2018 Nintendo Direct presentation, there was a gameplay livestream for Pokémon Let's Go Eevee and Let's Go Pikachu, and it answered a lot of questions about the game.
We got confirmation that wild Pokémon encounters are all about berry throwing and timed ball throws, with no battling, but encountering these wild Pokémon will help level up your party. Catching a wild Pokémon will grant your Pokémon party experience, and as they level they learn new moves in the same way they did before. Praise be, we can still grind wild Pokémon for experience.
Based on what was shown, it looks like Pokémon learn moves at the same levels they do in the mainline series. Battling trainers also grants experience to level your Pokémon but, rather than battles rewarding you with money, you're rewarded with additional Pokéballs.
It was also shown that you can have one Pokémon following you, on top of the starter Pokémon that hangs out on your body. Your co-op companion player can also have a Pokémon run around behind them too.
If you enter a trainer battle while in co-op, you take on the opponent trainer two against one, meaning that battles do not scale up to account for co-op. The opposing trainer doesn't send out a second Pokémon or take a second turn to compensate, which seems a bit unfair.
Companion Pokémon do scale in size to some extent, so an Onyx companion Pokémon will be considerably larger on-screen. It seems size is the key factor in whether or not you can ride a Pokémon on the overworld map.
Your rival in Pokémon Let's Go isn't Gary, as it was in Pokémon Yellow, but a new rival called Chase. He's less mean than Gary, fairly friendly in fact, and easily scared. Kids these days, eh?
Pokémon Centres work as they do in the core series, a one-stop healing shop.
There are events and quests in Pokémon Let's Go that didn't exist in Yellow. One example shown was a woman who asks you to look after her Slowpoke while she runs some errands. There's a unique animation as you stare into the creature's face, and you're eventually rewarded with an item.
We also saw some of the first Gym in Let's Go, Brock's gym in Pewter City. Upon entering the gym, you're forced to show an attendee that your party contains a Pokémon that has type advantage against rock types, a new hurdle that will ensure players understand type matchups. It explicitly tells you which types of Pokémon will have a strength advantage. It was shown that you can battle Gym leaders in co-op, and those too do not scale up to account for that second player. Poor Brock!
According to a statement made during the livestream, the rumble in the Pokéball plus controller is stronger than that of a regular Joy-Con, but obviously we can't confirm that. The livestream re-confirmed that the Pokéball Plus is the only way to get Mew. When you buy the peripheral, even before you connect it to the game, you'll be able to hear Mew inside, apparently. You'll be able to transfer Mew over to the base game at any time you like.
There is an LED light ring on the Pokéball Plus that changes colour based on what type of Pokémon is inside it. There was also confirmation that it can be used as the Pokémon Go Plus peripheral for Pokémon Go, meaning you can use it to play Pokémon Go with your phone screen locked or the app minimised, clicking a button every now and then to catch a creature based on flashing lights on the ball.
Multiplayer was shown during the livestream, confirming that local and online trading and battles will exist in the game. When playing local multiplayer, each player taps in a 3 digit code of Pokémon images, and will then pair with their friend who has typed in the same images. Trading seems to work exactly as in the main games.
In terms of transferring Pokémon from Pokémon Go to Let's Go, you'll have to go to a new location called Go Park (which replaces the Safari Zone). Pokémon sent from Go will then appear in Go Park, and you'll need to catch them again. It was confirmed that Legendary Pokémon can be moved over via this method, as we saw Moltres present in one of the parks. CP in Pokémon Go will dictate strength in Let's Go, but the rate of conversion was not explained. They also failed to address what happens if you fail to capture a Pokémon in Go Park. Is it gone forever? Does it stay in Go Park for you to come and try to catch again?
Let's Go will allow you to send duplicate Pokémon to the professor, much like Pokémon Go, in exchange for candy, but the candy works in a different way. Instead of candy specific to the duplicate Pokémon, you get candy based around core Pokémon stats, like Attack or HP. These candy can be used to raise those stats, which is your incentive to catch duplicates.
Lastly, the presentation ended with confirmation that in Pokémon Go, Unown will be appearing in the LA area, spelling out the letters of Let's Go.
There we go! Some questions still linger, but a lot of things have finally been answered. Right, time to go out and do some Pokémon Go raids while I count down the days...