Update: it might actually be using steganography.
Using the different pixels some sort of a file might pop-up.
Might not be much either, but maybe only the games in-which "unknown developer" wrote on the picture accompanied to the download page "this is not a screenshot"- are actually connected.
All in all, "this is not a screenshot" is written only on "On the Edge", "DPTG" & "Six Books" [the word "screenshot" is mentioned in "Tits & Boobies" and "en wye" though]
Hey there.
So after playing around with the Solution.png on Photoshop (Basically just rotating, mirroring and changing the Brightness and contrast), this came up http://imgur.com/a/tbEmY .
The Morse code says "look inside". Still, no clue of the meaning of the white dots.
-It could be meaningless, but when doing the opposite (brightening the picture instead of darkening it), the shape behind the text clearly seems like a diamond (may be my imagination, but I'm not sure)