Its the classic snake game for both iPhone and Apple Watch where you swipe the screen in the direction you want the snake (green dot) to go, collecting all the red dots you can find.
Dont touch your own tail and dont exit the playing area or youll be forced to start over.
Its fun, its easy and its a challenge as your tail grows and grows.
Finally a game designed for the Apple Watch for those times you cant use an iPhone.
Have fun.