I have begun working on a new game mode for Astariel.

I am calling it "Storm", and, as the name suggests, will feature a drastic increase in enemy bullets. To compensate, regeneration rates will be doubled and the number of technologies required to unlock the highest weapons will be greatly reduced. I am testing it now and it plays hard and fast. 

Other changes to the next version include:

• Speed and slow powerups now affect alien bullets
• Boss missiles can now be shot down
• A max cap has been placed on mines and homing missiles spawned

I'll repost here as soon as this update is complete...