itch.io

1. Fixing the score text in level 2. - This would not constitute as a significant change.  
2. Adding more enemies into level 2 and making it different. - This would not constitute as a significant change.  
3. Changing the text colors in the main menu. - This would not constitute as a significant change.  
4. Changing the fonts if possible. - This would not constitute as a significant change.  

A significant change is something that consists of more than dragging more enemies on the screen on changing a value in the inspector. I would suggest changing levels entirely for modification or changing UI lay out to be different. If you create a custom font that would be significant.