Dr. Mario World is Nintendo's next game to be released onto Android and iOS devices and it's coming this month, specifically next Wednesday on July 10. Leading up to the game's release Nintendo has now shared a video on its Nintendo Mobile YouTube channel which shows off the multiplayer aspect of the game so players can have an idea of what the gameplay will be like.
To play with your friends you will need to connect either your Facebook or Line account to Dr. Mario World. The video does not describe whether or not you will be able to play against any of your Nintendo account friends, but it would be an odd thing for Nintendo to disallow this perk so it's possible that Facebook and Line account links are there as an added level of connection for friend play.
There are two separate layers to the friend connection in this game. One is for viewing your friends' stats and the other is for playing against them in versus mode. If you're curious to see how you stack up against your friends you can view their gameplay profile and see their progress and different stats for the games they've played like how many stars they have, how many versus points they've acquired, and what stage they're currently on.
You can send them hearts too, which can be done once per day for each friend you're connected with. Hearts are kind of like your energy for playing levels, so obtaining any extra is always going to be a good thing.
As for Versus Mode, since everything is in real-time you'll need to work quickly if you're going to win. The main goal is to be the person who doesn't end up with a completely full stage, and part of how you do that is killing the viruses on your own stage which fills up your attack meter. Once the meter fills up all the way you can send viruses over to your opponent's stage to stack them with viruses till there's no more room left, and then you win.
Adversely, your opponent can do the same thing to you so you definitely want to be on your toes here and watching for any incoming virus attacks that you may need to get rid of. Each Dr. character in the game can have a different level of attack power and this is what dictates how many viruses you send after you get a full meter and launch an attack, so also keep that in mind when selecting your own character and when seeing who you're playing against.
High Defense power is important to keep an eye on as well as it could mean the difference between sending over some viruses and having the attack blocked. If you're eager to dive in and start playing against your friends, you only have one more week to wait for Dr. Mario's official release, and after that comes Mario Kart Tour which is also launching this Summer, giving you plenty of new Nintendo game content to play on your device.