Kirby as Simon Belmont is neat, though the cross boomerang looks more like a cross, Nintendo probably wouldn't have it that way (re: religious references). Also, his whip hides "FLICKY", making it look like a bad word.
I like how just below the center you see Wonder Boy and Master Higgins both reaching for the axe (Wonder Boy and the first Adventure Island game were essentially the same), but I'm pretty sure official artwork wouldn't make an in-joke that might make one hesitant to download both.
Also, there are obscure characters...nearby those two above, I see the guy from Rockin' Kats. He's kind of obscure, with only one game, as far as I know. Then there's also Mighty Bomb Jack, Kid Dracula, Mappy, Sonson, Solar Fox (I think that's his name), the Parasol Stars heroes, Firebrand, TwinBee, a ship presumably from one of the Darius games, Ebisumaru, Bubbles, the kiwi from Kiwi Kraze/New Zealand Story...and other characters more well-known and less well-known.
Unless all their games are guaranteed to come out for the VC at some point, and for the other reasons mentioned above, it's most likely not official, but as a fan-made piece of art, it's an interesting who's who of classic games...now I feel like finding some Where's Waldo books.
(Someone should make Where's Waldo-style books, but with video game characters in video game settings. It's fun to find Waldo in a crowded airport, but I'd rather look for a Podoboo hidden among the Rinkas in Tourian.)