Nintendo's biggest game of 2018 is getting much better as we move into 2019

Starting in late September 2018, Nintendo's Switch console now requires a paid subscription to Nintendo Switch Online in order to play most online multiplayer games.

There are exceptions, like "Fortnite," but the vast majority of Nintendo Switch games with online components — like "Mario Kart 8 Deluxe," "Splatoon 2," and "Super Smash Bros. Ultimate" — require the paid service for online play.

More simply: You can't play any of those games over the internet without paying $20/year for Nintendo Switch Online.

The service comes with other features, like access to a growing library of classic NES games and the ability to put save games in the cloud. And, at $20/year, the cost is significantly lower than competing services on PlayStation 4 and Xbox One.

But considering that "Super Smash Bros. Ultimate" was the biggest Nintendo game of the year, and the fact that it has a major online component, and the fact that Nintendo started charging for online gameplay in September, having major connectivity issues at launch wasn't a good sign.

Starting soon after launch and continuing through the end of December, "Super Smash Bros. Ultimate" has been updated three times (including the "day one" patch).

Nintendo's patch notes are vague, containing broad statements like, "Several issues have been fixed to improve gameplay experience."

But the proof is in the playing: The game's online stability has increased dramatically since launch.

I can attest to this personally, as I've played hundreds of matches online in the last three weeks, and anecdotal evidence from other players I've spoken with indicates the impact has been widespread.

In a complete flip, the majority of games I encounter are smooth. I rarely encounter lag, and even more rarely encounter lag on the magnitude of what it once was. For the first time ever, Nintendo has an online experience befitting its best multiplayer game.

The game's creative director, Masahiro Sakurai, said in a recent Famitsu magazine column translated by Nintendo Everything, "Now that Ultimate is out, is the online matchmaking system not working out well? I’ve got my own suspicions, so I’m going to look into it some. I’d like to make adjustments wherever possible to fix it wherever it needs fixing."

In so many words, it sounds like more updates to the game may be coming.

But what we know for sure is that "Super Smash Bros. Ultimate" is getting even more characters in its already robust roster.

Piranha Plant, of "Super Mario Bros." fame, is joining the roster — bringing the total playable character count to a whopping 75.

That's not counting the addition of Joker from the "Persona" series, who's scheduled to arrive at some point in 2019, as the first of five additional downloadable characters:

Thus far, five total fighters are being added to "Super Smash Bros. Ultimate" as additional content. The grand total of playable characters will hit 80 by the the time all the extra characters are available (including Piranha Plant).

There are no set dates for new fighters just yet, but the company says they'll all be available before February 2020.

Nintendo is selling a "Fighter's Pass" that offers access to all five of the upcoming downloadable characters for $24.99. Piranha Plant is free if you buy "Super Smash Bros. Ultimate" before January 31, 2019, and will otherwise cost the same $5.99 as all other individual downloadable characters.