Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics

Yep, this has been addressed on a few other threads, but you can switch to a new set of 4 colors for different levels as long as the number of unique colors on screen always is 4 or less.

I think most people are sticking to one palette for simplicity's sake but if you have it in you to switch from place to place, you totally can!