I could be wrong but I read it as "The people who play it need to be able to tell that its inspired by the video game named 'Pong' and you are totally free to chose how to interpret this. You can make it play very similar to Pong but with a unique visual design, story or new gameplay mechanic. Or even a game thats very different from Pong that has a story about (Ping) Pong. Just be creative ^^"
