Changed controls and added a stage!

Hi again,

I have finished another stage that takes advantage of the new ability - Rapid Shot. Now when you flip your ship, you shoot bullets rapidly in an arc, allowing you to destroy enemies from above!

Makes for more interesting levels, where enemies can come from right, left, and now top.

Other changes:

- controls are more in line with other shmups (Z to shoot, arrow keys to move, etc.) I will eventually work on control customization and game pad options (Xbox, PS5  controllers)

-Game over now sends you back to Level 1 (retro style)

Enjoy!