-Added Training Difficulty.
-Reworked enemy Spawn System. Less time between waves.
-Slightly increased Upgrade item drop rate.
-increased missile explosion sound effect radius depending on the size of the explosion.
-Made enemy level ups less dependent on difficulty (previous patch).
-Improved enemy AI
Bug Fixes:
-Fixed a bug where the game would crash if you closed the Level up notifier through the x,
the game would crash.
-Largely fixed a bug where all sounds would stop for a few seconds due to all enemies in a wave
spawning at once, by making enemies not all spawn at the same frame.
-Slight performance increase due to enemy changes.
-Fixed a bug where the main menu starting sound would get interrupted by other sounds.