It seems like all gaming systems must have their Baseball game, as early as 1978! Indeed the RCA Studio II, the Fairchild Channel F, the Bally Astrocade and the Atari VCS all had their Baseball game!
The controls are similar to other Baseball games. The outfielders are moved with the joystick, though you can't move them after the ball is pitched. They're spaced a little oddly, so there's usually a gap in right field that the computer player manages to hit to more often than not. To pitch, you send the ball with the fire button and control its path with the joystick. To bat you simply press the fire button.
The Bally's players are animated better, so if I had to rank this one by graphics, I'd place it as better than the Fairchild's version but not as good as the Bally's, based on overall look and player animations. Control-wise the Bally outfielders had a better range of motion, without the gap that the APF players can't seem to fill. At bat, it seems harder to get a hit on the APF than it does on the Bally and I don't feel I have the same control over where the ball is hit. Pitching is pretty similar in that you've got a lot of control over the ball after you "throw" it and it is fun to try to fake out the person at bat with wildly curving balls that they swing at anyway.
You can play with a friend or against the computer.