Tennis Activision.
It's really easy to look at this game and believe it to be incredibly primitive. I remember writing it off as just far too simplistic. I had played Pong for years and was more or less fed up with tennis games so I saw this just as a variant of that with a change of view and a nice slap of fake 3D paint applied to it.
Even though my gaming then was made up of a healthy ratio of single to multi-player with siblings and cousins, for some reason I didn't think I would get any value out of this. We were big Wimbledon fans at our house - this was the era of Borg, McEnroe et al and in the UK tennis was a big thing. So it's still a bit of a mystery to me why I didn't get this.
Recently I tried this on Stella. The game controls are ludicrously simple. You only have to press the button to serve. After that the ball is hit automatically - so making it feel at first even more like a tarted up Pong.
But nothing could be further from the truth.
What I found was that I was getting my ass handed to me by the CPU. It was like playing against a brick wall. I couldn't win a game. I found it hard to even win a point!
The more I played, the more I could start to see how important position is. It dictates whether you play the equivalent of a forehand of backhand shot which had a big input into the direction you return the ball. Also the game detects which part of the racket makes contact. I don't know how many angles of return there are but there are several - at least as many as in 2600 Pong (which has 5). EDIT:Just read that difficulty switches affect this.

So I found myself starting to be able to position myself to make angled returns and start to win some games. But it becomes pyschological (as much as it can with a CPU opponent - but I can only imagine how good this would be in 2P mode). Position is everything.
Well - not quite everything.
Timing is important too.I noticed sometimes the speed of the ball would change. Sometimes I would hit a cracker. Then I realised the height of the ball is important too. Hit it when it is high and you get better speed - and maybe even better angles. Can't definitively say yet if that is the case with angles, but I suspect it is. It feels it anyhow.
But to be able to have the time to wait until the ball is higher means predicting the opponent and being in the right position early.
I am also starting to think that hitting while stationary or while moving might make a difference too but I can't be sure.
In short - this is a deep game. A really good recreation of Tennis which I used to play in school. It feels like playing Tennis - albeit while sitting on ones backside!

There isn't as much emphasis on the domination of having the serve but that isn't really that big a deal. You can still dictate the rally a bit because you can choose to come into the net off the back of it.
This is a masterpiece of game design. A real gem in the Activision crown. I know I would have got many many hours out of this. My brother and I would have caned this game. And our regular MP sessions with cousins staying over would have benefited from it too. I regret not getting this game. I reckon my father might have even tried this. He loved Wimbledon and played the odd game of something with us from time to time.
Atari brought out
Realsports Tennis later on on the 2600's life and it seems to have similar depth but is maybe even slightly more nuanced. You can change the settings so that hitting the ball isn't automatic, and hitting the ball while moving forward can make the player smash the ball. When retreating it creates a lob shot - so adding more options for attack and defence. This game has a bit more graphical flair being a later game but either game will I believe deliver a great game experience - even today.
I'm a big fan of Sega's Virtua Tennis and Nintendo's Mario Tennis. It's probably the best sport for videogame treatment. The entire court can be covered by a single camera view with minor adjustments. And it can facilitate 4 players in modern versions. Both Sega's and Nintendo's games enjoy pick up and play control schemes - and like their 2600 ancestors soon reveal hidden depths.
Even if you play these modern games I firmly believe you will enjoy these two early games. I really , really wish I had owned one of these in the day.