You can download the demo here (no emulator required) and check out the Wikia page for the project here.
While nearly everything from third generation on will be incorporated, there will be no Mega Evolutions and Fairy-types since, at the time of the project's creation, these mechanics were not supported by Essentials. The game itself runs on RPG Maker XP and uses Pokémon Essentials, which is a set of scripts and resources that allows users to create Pokémon-style games. After you reach the last town and defeat the first Gym Leader, you can't progress any further but are free to train and explore the areas to your heart's content. Demo length is roughly one to two hours and includes three towns to visit, about ten Pokémon that can be captured and two caves to explore (with no Zubats!).
