Minor changes

-Slightly changed the color of all the red text and icons in the "YOU LOST" slides (from RGB 255 0 0 to RGB 224 0 0). Also changed the border color to #E04949

-Changed the color of the obstacles in dark mode to RGB 192 0 0

-Added a slide with instructions about controls and installation. It will only be shown in the first file you open, it will not be shown when you change language or toggle light/dark mode