You are playing as Pac Man (the yellow guy) collecting the tiny yellow dots and the big yellow dots. The tiny dot adds three dots to the counter, and the big dot adds 5 dots to the counter. When the ghost is orange you have to run away, but collecting a big dot also makes the ghost turn blue. When the ghost is blue, you can eat him for extra points. Tell me in the comments your best score.
All by me and also don't press the up left down right arrow keys in order unless your score is really low. No seriously though.