So. Much. Potential... Couple of things you need to add, then this can be popular :D
#1 Painting while moving
#2 Sharing paintings with others over Kong, maybe even using then as avatars ;D
#3 Give a tutorial at start, I literally had no idea what to do going into to it.
#4 Perhaps an optional outline of the keyboard?
Dear Raiyumii, that climb at the final puzzle, where the wall is tilted in on you? That is single handedly the most rage inducing thing I have encountered in gaming history.
I think a nice block idea would be an RBG Block, essentially a block where you can enter RBG values to get specific colors. This would be really good for pixel art and level design... either that or a hexadecimal block ;)
 "Super SOPA Bros."){kind=icon}
 "Keyboard Painter"){kind=icon}
 "Infectonator: Hot Chase"){kind=icon}
 "Hexagon"){kind=icon}
 "Sky Island"){kind=icon}
 "The Valley Rule"){kind=icon}
 "The I of It"){kind=icon}
 "Dino Run"){kind=icon}
 "Sandbox Hero"){kind=icon}
 "Frontier"){kind=icon}
 "Relive Your Life"){kind=icon}
 "ButtonHunt 2"){kind=icon}
 "Learn to Fly Idle"){kind=icon}