director Masahiro Sakurai said: "Pic of the day. A panel in the Challenges area will unlock everytime you clear a challenge. When you unlock a panel, you'll see hints for unlocking panels directly adjacent to it on all sides. And this time, each panel will unlock pictures related to the challenge. This is tougher than it looks, you know? The challenges in the 3DS version are a little on the easy side, but the Wii U version challenges might be a bit trickier." August 27th. Yeah not exactly saying character unlock methods are harder. Sorry. I feel it is sort of implied though.