These days, there's a lot of chatter about multiplayer games which have multiple front ends. We've talked about it, you've talked about it, they've talked about it. Here's some fun details you may have missed in the oompa-loompa vibe.
If you have front ends with different difficulty levels / gameplay capabilities, it is unbalanced. If it isn't, people will naturally tend towards the clearest representation.
Meaning that if your tennis game is the same difficulty and plays the same way as your pong game, people will start to tend towards pong. Why? Because it's crisper, cleaner, and more efficient. IE, somewhat easier. That is important to more advanced players - more important than the graphics, which we've already relegated to background noise.
If your tennis game and your pong game are different difficulties, players will tend towards the easier game, just as before. Chances are, this will be your pong game, rather than your tennis game. The magical hallucination that weak players will choose the easy game and hardcore players will choose the hard game is bunk.
Oh, this will also cause your game to lose "depth", meaning that hardcore players will get bored of it quicker. No, they won't simply switch over to the harder game when they "master" the easy game. They'll probably try it, but finding it is simply a less efficient version of the first game, they won't care.
There are two ways around this "players tend to choose the advantageous way" problem.
The first is rewards. If the harder game has mightier rewards, players will gladly play it. For example, unlockable costumes or being a subcomponent of another, "wider" game, or playing for real money. The difficulty here is in choosing a reward which (A) won't run out and (B) won't have players bitterly complaining about unfair advantages and easy-game players spamming the grid to uselessness.
The other method is automatic scaling. If Anne wins at least 50% of her games and plays at least ten games, she is automatically upgraded to the more complex game, or at least locked from the easy game.
This is flatly a bad idea. First, Anne might really like the easy version and have no urge to change modes. Second, if you're going to do that, it would be easier to simply have ONE game with a handicap system. That's better because it also adapts to player's relative strengths, rather than relating a player's strength to some "global pool".
Now, I'm not saying that having multiple faces to suit players with different capabilities (both hardware and skill) is a bad thing. I'm saying that it's a bit more complex than the impression you might be getting.