Hi! Feel free to have AtariAge built you carts of the game, as long as you don't resell them for profit (I mean, the game is freeware).
This game does require a Melody board to work on real hardware. The Melody board uses the same ARM coprocessor as the Harmony cartridge, but for a single fixed game instead of an SD card.
By-the-way, I do plan to make an expanded / full version of this game someday, and hopefully make it good enough to be worthy of a boxed physical release :)!
In the meantime, I'm glad that you're enjoying this Jam version enough to want to have an actual cartridge of the game!