Stealth v1.4

Aesthetics: Took away the text on the walls as it detracted from the game-play and immersive feel, and instead added robotic code-like text at the top for instructions. Changed the lighting to make it slightly darker in general, as it felt too bright to be a stealth game. Removed green light from player. Edited the level select page so all levels are accessible from there (bug fix from before).

Changed the background music when the diamond is collected so it isn't as repetitive (going to edit it more in later updates but just a quick fix for now)