Gave all buttons a background image so they can easily be identified from just text.
Added a timer next to each power-up so the player knows how much time is left for each power-up.
Made the reset button in the pause menu accident-proof by adding a confirmation screen that appears first.
Made it so that you can now use the power-ups shop in endless mode too.
Made it easier for players to tell where they are getting hit from, made it easier to avoid enemy attacks, and nerfed the first and last boss fights by making all bullets larger and slower.
Bug Fixes:
Fixed a bug with endless mode where the background music wouldn't play.