The bar at the top is your experience bar. Jump on top of the red object to "kill it" and gain experience points. When you've gained enough, you will raise one level, and raise attack power. More attack power means less hits until the red object "dies." The higher your level, the more experience points it takes to level up! See if you can get a critical hit! (; Use the arrow keys to move (up arrow to jump). Credit to dudey100 for the ideas for the critical hit!