Level 7 - Just let Beavus run straight off the platform twice, then just jump at the very edge and you will bounce back to the begginning. Level 10 - Don't stop jumping until all the logs have been consumed. Level 13 - Run forward and jump over the spring when Beavus' teeth are almost touching the spring edge. You will be able to jump over the spring and consume all three pieces of wood without dying (kind of risky).