1. Click Green flag. Read help and click to continue. 2. Use arrow keys to move the snake. 3. Eat apples to gain points and increase length and speed. Eating bad cherries loses points and causes length and speed to decrease. 4. Game terminates when Snake touches any of the screen edges or obstacles or loses all its body.
To understand how I designed this program, look up this design document: http://www.abhayjoshi.net/spark/scratch/blog/snake.pdf
