As an entry level task, a robot can be realized by defining a reward function. A reward function isn't about programming the robot itself, but it defines the game. Or to be more specific, it's a scoring algorithm to evaluate the actions of the players within the game. The player's role can be fulfilled by humans and robots as well. For example, in the famous pong game, the scoring mechanism decides, that player1 gets a +1 score if the opponent player wasn't able to block the ball.
A good scoring mechanism provides a continuous reward. The game can be paused at any moment and the algorithm determines, who has won the game with a floating point number precision level. Visualizing a reward function or a cost function as well, is usually done with a potential field which is heat map.