When the player is knocked down at low energy level there is a chance to fully charge up a power meter that appears for a few seconds. If successful, the player's character gets up with a lightning charge and delivers powerful attacks.
At the half of the first stage, you can choose the course for continuing your way : in this way, you can modify the level sequence and the relative difficulty for those.
After you've beaten a boss at the end of the level, he will be available as a playable character, and you can also choose him to play the next level : every time you beat a new boss, this will be added to the playable characters rooster. These characters are :
Pharaoh, an ancient very powerful pharaoh, you can find him in the Aquarium stage;
Mavella, a beautiful woman with red hair and equipped with a whip: she is waiting for you in the Funnel stage;
Garuda, a very strong redskin, you'll find him in the garden pool;
Gonza, a powerful sumo fighter with devastating slaps, you'll find him in the japanese house;
Chen, a chinese fighter equipped with a letal chinese sword, he is waiting for you in the disco stage, after the casino.