Sonic20xx
Boring roster, lack of content, abysmal online that is worse than Brawl's online, and terrible DLC slots. It's the worst Smash game by far.
1999
Lack of content is the game's biggest problem. Outside of that, good game.
The magnum opus of the Smash series and it will stay that way. Competitive wise, it is disappointing. Casual wise, objectively the best in the series.
Wasted slots and I hope Sakurai never worked on another Smash game.
2015
Personally, it is not the peak of the series like the fanbase think it is. It is painfully the most overrated game in the series.
A big improvement over Smash 64 in any way.
Personally, it's a complete disappointment altogether. The gameplay is alright but that's about it.
Better than the Wii U version, but that's not a high bar to stand on.
2001
Best atmosphere in the series and the gameplay is still solid.
2003
Personally, it's not bad but it's not good either. It's ok.
Best in the series by far.
2008
The gameplay may be better than 3, but it doesn't excuse the fact that you're playing half a game.
2019
While it is a well-made game, it is missing something. Especially near the end.
Has the best campaign of the franchise and the multiplayer is awesome even if it doesn't beat MW2's multiplayer.
Is the game unbalanced? Yes. Is it still an awesome game despite that? Yes. It in fact helps the game than hinder it.