Slight Improvements

These were the changes made for the improve your game jam. Unfortunately, I had little time to actually make some significant and visible changes. Most of it is just cleaning up spaghetti code from the original but there are some new things to play around with.

Changes:
- Switched the level select song from Yggdra Union GBA version to the PSP version
-Reworked later levels, some of them were even unbeatable at launch!
-Fixed a bug which prevented items from spawning in chests sometimes.
-Added a unlock all levels code! Hold Up+Down and press C if you want to get everything right away

Still a lot to improve on. A proper ending is still on its way and a reward for 100% completion too