Oh no, it's a Pokémon hack (way to change it up, right?), specifically Emerald. You can add and change whatever you want as long as the console's hardware can handle it. The only reason why 99% of Pokémon hacks stay true to their roots is because it's very hard to implement new features and to manipulate current ones. For the Gameboy Advance games, you need to be familiar with ARM and THUMB assembly and understand what all of those hexadecimal bytes mean when using a memory viewer. My specialization is music hacking. I export music and instruments from the DS Pokémon games and import them into my Emerald hack. One of my goals is to reduce the amount of chiptune used in Emerald to as low as possible.