If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Mordecai and Rigby adventure on the tree, which many traps and monsters are always waiting to harm Rigby. Help Rigby find a way to the tree house by using Up key to go upstairs, left and right key to move left and right. Down key to move down stairs.
Arrow keys - To move.