Yea, the shop was added in the last few hours and I wanted a lot more upgrades to be available. The interesting part about game development is that I have full control and any time I used a number in code, that number could be available to be an upgrade. I was planning on adding things like longer invincibility frames, more health drops, faster paddle speed, longer aimer, enemy spawn time, bigger paddles, etc.
The prices were extremely last minute and I just had to guess good prices and price upgrade rates and how the enemies would scale.