The biggest challenge we have yet. The image comes from the Hidden Numbers Unused Levels Archive. The checklist costume contains 42 numbers, each having a color code. RED ㊗️ - Incomplete YELLOW ☢️ - Unvectorized GREEN ✳️ - Complete
Credit to @aidenneuding for starting the challenge. And by extension, credit to WellGames/Mysteriez! I found a slightly later version of this image with more numbers, some of which have changed locations. I also found the original screenshot (or rather, screenshots) used, and reuploaded it in a lot better quality. By the way, I updated the count to 42 since that was the intended amount of numbers to find in the image. And as for why 28 on the checklist is upside-down, you should probably review the original game.