From Open Pixel Platformer Wiki
DawnBringer presented this 32 color palette in April 2013. This has been the official palette for the OPP from on the start.
"I have been working on a 32c pal since the DB16, but 32 colors is far more complex than 16 when you try to make all things work optimally together. Then when Hapiel of PJ accidentally asked if I could help out with a 32 color palette for the Open Pixel Platformer Project, it was a good incentive to wrap this one up. " -DawnBringer