Added numberOfEnemiesToReleaseAtATime and MaxNumberofEnemiesOnScreenAtATime to level settings.

Created a stats manager to display player health, score and various other stats.

Tracking stats of the number of enemies that you have encountered and the number of enemies that have been killed as well as your kill percentage. At the moment the I am displaying all this information on the screen through the stats manager.
Displaying game stats at the end of each level.
Animating the players health. When the player loses a health point a heart will become empty. If the player has one health point left the last heart will animate beating.
Doing some really neat with sounds. When the player has one life left not only does the last heart animate beating but we play a heart beat in the background to instill a sense of doom upon the player. Additionally all other sounds are turned off. It makes you feel like your moving in slow motion when you can hear your heart pounding through your ears.
Implemented a GameSound class that wraps FlxG.play. This allows me to control when sounds are played. If the player has one health left it will not play any sound effects. The health manager will continue to play the heart beat sound because it uses flxG directly.