If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You play the role of a fox who needs to escape the forest. The reason for escaping is because it looks like stuff is falling from the sky as if the forest is falling apart. The only thing you need to worry about is jumping and as well as jumping over gaps there is also tree stumps and other things you need to avoid as well. Don't forget to collect as many acorns as you possibly can to make sure you get a high score.