If Pokémon Ruby and Sapphire were made for the original Game Boy. Found the above Gen 1 style fanart in a thread on /tr/. It seriously looks like legit Nintendo art from the 90’s.
Turns out, Pokémon ROM hacking group Melash Games actually made an attempt at de-making Ruby/Sapphire/Emerald in the form of Pokémon Ancient Emerald back in 2009. The site looks pretty stale right now with no updates or indication as to whether or not the project’s still being worked on.
Below are some Pokémon Ancient Emerald pics and a video of the game’s intro.