After playing Mario Golf on the NSO, I tried to give a shot to the Tennis counterpart, expecting a similar, kinda just okay/ mediocre experience.
And what I played was not amazing, but still incredibly solid.

For what it is supposed to be, a quirky tennis simulator with Mario flavor, it does A LOT of things to make it stand out.
It has an incredibly charming opening cutscenes that gives life to a lot of the mario cast; and it adds such bizzarre pics to the roster for the time, like the princess from that Land game, that miniboss dinosaur from SMB2, a random Boo and Shuguy (that weren't really that big of an enemy at the time), both DK and DK jr, and some weird camelot OCs, including what would become one of the most memorable nintendo characters. Not to mention that compared to othe sports titles, Mario Tennis builds different modes out of the mario universe: we got classic tennis matches and tournaments, but also the ability to play items on Bowser castle, and even have minigames themesd around piranha plants......

Even at the time Camelot was able to take the Mario world, shape them as they wanted and add so much more charm and personality to it. I highly respect that, even though the formula of Tennis here is... just rather simple and repetitive.

While the skeleotn of the game is "just tennis", the flavor of Camelot led to a charming experience, that is able to set the standards that will make the future Mario sports games so memorable.

Years ago, on a Super Mario messageboard I used to frequent (Lemmy's Land Forums), we played this elimination game involving like 50 different Mario games. The idea was that each person would "Save" one game, so at the end of the round, the last game to be "Saved" would be eliminated, and play would restart. I dunno if this sort of game is really played much anymore, but it's the sort of thing you used to see all the time on messageboards. Anyway, this one guy really liked the original Mario Tennis - if I remember correctly, his love was based entirely around playable Paratroopa - and would make a point to rush in and "Save" it at the top of each round. It got to a point where "Save Mario Tennis" became an in-joke around the community, and any time Mario Tennis on the Nintendo 64 was mentioned, someone would be quick to "Save" it. Or that just became the name of the game itself: "Save Mario Tennis".

I mention this because, after a few non-starter attempts at unlocking both characters and one finally successful one, I can't really get the adoration for this title.

Mario Tennis is an extremely important Mario game. Since Camelot needed to pad out the roster with Doubles partners, the team got creative with their picks for playable characters. This is the game that introduced Waluigi as Wario's Doubles partner, and while that's not the move I would've made (personally I probably would've stuck Captain Syrup in there - yeah, they're enemies, but that's what Wario deserves), I'd be lying if I didn't say I loved what the lanky loser has become over the years. This is also the game that brought back Princess Daisy and Birdo, elevating these two supporting ladies into fairly prominent roles going forward (as well as cementing the pairings of Daisy/Luigi and Birdo/Yoshi). Playable Boo and Shy Guy would become common sights going forward, but this is where they got their start. Yes, Paratroopa over Koopa Troopa is a fun pull, even if it was probably just made because animating flight is easier than animating walking. The only real non-starter advanced by this game in the roster department is Donkey Kong Jr., since Diddy Kong would make for a far more logical Doubles Partner for DK going forward and Petey Piranha would fill in as the usual fourth Power character - but DK Jr. is a fun inclusion all the same, just someone who wouldn't see much of an expanded role in the future.

But I'll be honest, the roster is the main thing Mario Tennis has going for it. Apart from that, the game is shockingly dry as a tennis simulator. Yeah, it lets you play tennis, and yeah, the characters have some different properties, but that's pretty much it. I guess if you really like regular ol' tennis, this is a decent enough simulator for that, if a bit stiff - I never feel like I have as much control over the ball as I want (but then I mostly play Speed/Power/Tricky characters). Personally, I find the whole thing pretty wanting for some sort of high concept, even if it's just a big aesthetic change in one of the courts. For goodness sakes, all of the unlockable courts are just reskins of the regular court with JPEGs of the Mario cast printed on 'em! Playing this after growing up with Mario Power Tennis, it was a huge disappointment.

The side content is a'ight, but pretty limited, especially for singleplayer. Ring Shot is probably the game at its mechanical strongest, since it teaches the player how to rally, and there's a nice tense cadence to building up points. Piranha Challenge is okay - fun to see the Piranha Plants doing something, even if they're basically little more than pitching machines here.

Bowser Stage is a fun idea and a weird assertion of Mario Kart in a non-Mario Kart setting, but I actually find the items themselves a little lackluster. The issue with using Mario Kart items is that you think they'll do Mario Kart things, so I kept trying to use the Starman to tank hits when it's just a power-up in this game. Shells are probably most interesting, since both lock down where the opponent's able to move, but they can't hold this mode on their own. Actually, it's the stage itself I like best, since it has a gimmick of leaning towards whichever side's weighted down - really would've liked to see more courts experiment with gimmicks like this.

I like the idea of Mario Tennis more than I like what it actually does, I think. Tennis is a sport I like to play, and the idea of stapling Mario characters on in there is a fun idea. I especially like the consequences the game's had on shaping the series, perhaps more than any other non-mainline Mario game outside some of the Mario Karts. But as its own thing? I'd much rather Save a later Mario Tennis.

I've never been any good at Tennis games. I don't understand all the different types of shots and when they should be used.

Mario Tennis does nothing to help with this. Not only does it not have any kind of tutorial, but the only instructions don't even cover all the different shot types, let alone the mechanics (I guess this stuff was in the manual back in the day).

I looked it all up online, but unfortunately found some info to be wrong (you do not hold down a button to charge, it happens automatically as soon as you press any button) which caused a lot of frustration. Once I managed to figure it out I did start to enjoy the game more, but I still made a lot of mistakes that I just didn't understand. Sometimes I'd hit the ball and get an "out" or it'd be too weak and hit the net, and I honestly have no idea what kind of flowchart between what the opponent does and what I'm supposed to do is supposed to be to stop all this from happening. Sometimes I'd hit the ball back with a regular "normal" (top spin) shot and it'd go to the opponents side with the marking of a lob shot, and I have no idea how or why that happens. It's all very confusing for me.

The game does run well though. It doesn't have any kind of story mode, but it does have a lot of objectives for you. The most obvious and the one with the credits involved is beating the tournaments, both singles and doubles. The credits happen after the third cup, but it's possible to unlock more.

Even the basic exhibition matches have something for completionists in it, since there's a data tracker that fills in every single time you play character A vs character B, meaning to fully fill out this section you'd need to win as every character against every other character (on the hardest difficulty for 100% since the difficultly beaten at is also recorded). So it's better than some games of this genre at the time which would basically just assume you're playing for fun (casuals am I right) and not care about your wins or your progress.

I was honestly surprised by the character roster. This isn't the basic MK64 or Mario Party rosters. You have some pretty interesting choices, especially for the time. Boo, Paratroopa (but no Koopa), Birdo and Baby Mario (and JUST Baby Mario) are all fun choices. This is also the game that introduced Waluigi, so you have to love it for that.

There's some bonus stuff that can be unlocked via the transfer pack and the GBC Mario Tennis game, but obviously this can't be done on Switch. It looks like you just unlock the human OCs from that game, and some courts. Still a bummer to lose out on content though.

The game is fun, but I think it's a bit too reliant on already knowing a lot about tennis to play properly, and having to read external material just to realise there's more than 2 types of shots in the game.

Let's face it, it's a good pastime. The main mode, tournament, is nice and well structured, with tournaments increasing in level, but not very practical because it can take a while and you can't save progress, but it's still a lot of fun.
The character selection is good, as always with Peach serving cunt. The design is very fun and even attractive, it awakens an inner child that makes you want to play.
The ring mode, where there are rings on the field and you have to cross them to score points, is difficult and a bit confusing, but it's still a good mode; the piranha mode, where piranha plants spit balls at you and you have to hit them back, is the coolest of all and the most enjoyable for me; the bowser mode is interesting, but a bit boring, because it's just the usual mode with power-ups that do practically nothing.

On the surface it's a simple tennis game with Mario characters, and that's exactly what it is but there's just something about it. The controls have aged remarkably well. They are easy to learn, hard to master which is what most games should strive for.

If you have a friend I recommend trying this out with them. When I first got my NSO+, we went through a bunch of games and while we kinda picked this one just for the hell of it, we kept playing and now it's basically tradition to play this game at least once when we meet up at this point.

I'd recommend playing doubles, it really is the most balanced and skilled way to play this game. For me, I really clicked with the way Paratroopa plays. He's speedy and can really slice through cracks in the opposition's defences.

Honestly just try this game. It's way more fun then you'd first expect.

Coming right off the heels of Mario Golf, Mario Tennis is an all-right enough time. The core gameplay still doesn't have any of the hallmarks of Mario Sports games as we know them now (i.e. character specific shots, fun courses, items, etc...) but its still fun enough to get by and significantly less frustrating than Mario Golf was as a whole. There is just about as much content via side modes and unlockable as there was in Mario Golf, but since this is a faster paced and less methodical sport like tennis all of it just seems shorter by nature of the sport. Where this game really shines though is in the charm department. Each character has their own victory animations and while simple they're fun and show that the developers put some amount of care into this game, there's also Mario who's the announcer for every match (for the matches Mario is playing in a random blue Mario with the same exact voice takes his place which is really funny to me) and his pronunciations of things are really charming and funny (the way Mario says Championship Point gives me life), it's small things like these that make up the game's personality but I'm really glad they're there, especially after just coming from a game that had nothing like that. Overall, Mario Tennis is a really simple game with basic tennis gameplay and a kind of minimal amount of content, but one packed with just enough charm and personality for me to like it.

I was honestly baffled by this
I went expecting cheap fun, but this is a great experience all around

The gameplay is polished and have some deegree of technicality, the characters play out a little different, large roster and each different court actually plays different. Also one of the earliest mario sport stuff. The game also have multiple unique game modes.

I think this is underapreciated for being a sports game that is not a simulator, but the game genuinely got me engaged. And there's a lot of challenging and understanding to be have here. Solid all around

Very solid tennis game for being the first in the series. Easy to pick up and play but somewhat challenge to master with all the different shot types and tricks. Subsequent games have made several improvements but this game laid the foundation for the series very well with its arcade-y gameplay perfectly suited for a Mario sports title. CPU opponents can be frustratingly hard on the major tournaments and it will require the player to explore the roster to find the best suited character to complete the game (typically powershot characters).