* Get the game on F-Droid
* A more explicit "wave" system
* Different types of fire. Slow enemies down? Area of effect?
* More enemy variety
* A way of increasing difficulty without it suddenly becoming impossible
* Mothership art
* A story mode?
* The main menu stars could do something silly and fun, like change colors,
	maybe taking the menu colors with them.
* Purchasable Mothership upgrades (like turrets), and make all upgrades exponentially more expensive for higher tiers
* Sounds effects for upgrades
* etc., etc.