Colours is a co-op and single player map pack for Portal 2 which features custom textures, sounds, and a whole lot of fun puzzles which focus entirely on synesthesia, puzzle solving, and cooperation. Features custom music, sounds, and more. Each map will be released as it is completed in order creating a chronologically episodic release, where each map will link to the next and if it does not then it simply resets.
Even though it's been more than a half year since I (or "we") played this mappack, I still remember it very well. It was the first coop mappack that my cooperative mate and I really enjoyed and had fun with. The puzzles may be tricky at some points, but it's absolutely fun playing them and they're definately still worth a play.
I recorded the blindruns, if you are interested in them, you can find them here:
Map 1: Youtube.com
Map 2: Youtube.com
Map 3: Youtube.com
Map 4: Youtube.com