The game doesn't launch until late June, but Nintendo will be holding a Pre-Launch Online Tournament (essentially a beta test) earlier in the month. You'll be able to choose from Mario, Bowser, Peach, and Yoshi, and can challenge the "online tournament" as many times as you like.
What's special about this pre-launch tournament is that players will get online and duke it out from June 1st through 3rd, via the Nintendo Switch Online service ... prior to the June 22nd, 2018 launch.
In addition to the demo, Nintendo also gave fans a quick glimpse at Mario Tennis Aces's Adventure Mode.
Players can expect to play as Nintendo's popular characters from several of their franchises and compete on zany courts using a combination of regular smashes and powered up smashes to win. The first trailer is an introduction to Mario Tennis Aces' story, while the second, longer trailer provides a more detailed overview of the game (the video is in Japanese, but it's easy enough to follow along).
Those that download and try the demo out will be awarded Mario's "classic outfit" upon purchase of the full game.
"Mario Tennis Aces" was announced by Nintendo during a surprise Direct livestream back in March.
As you win online matches and earn points, you'll unlock an additional five characters, as well.
Or if you're like me and don't wanna get whupped by some random digital "Roger Federer" or "Serena Williams" you can play it safe against a computer controlled opponent in offline singles play.