It's a good year for prequels with the word "rogue" in the title. We have, of course, Rogue One: A Star Wars Story, a now on the slightly more illicit side of things we have Metroid: Rogue Dawn, a fan-made hack of the 1986 Nintendo Entertainment System game Metroid that seemingly takes Gareth Edwards' film as its nominal inspiration. Both take casually dropped lines from their parent creations and use them to give us new and memorable adventures.
If that sounds like something you want to play, I recommend grabbing it before Nintendo demands these developers cease and desist, which will make it harder, but certainly not impossible to find.
Fan-made hacks get made all the time, of course, but what makes Rogue Dawn so remarkable is that it's so polished it looks like something Nintendo itself might have had hidden unreleased in its vaults somewhere. It's barely even a hack, as designers Grimlock and Snarfblam used Metroid's engine to make their game essentially from scratch over the course of two and a half years, creating entire new tilesets and with composer Optomon writing a fantastic original soundtrack.
In some ways, it's a more visually appealing than the original Metroid. The color palette might be a little drab and repetitive, but Rogue Dawn makes frequent jumps in settings from metallic research facilities to caverns crawling with unearthly life that keep the surprises coming. Unlike the original Metroid, it even has rain, and according to a playthrough of the beta on YouTube, there's a whole secret area that takes 1985's Super Mario Bros. as its inspiration.
Rogue Dawn builds off of a line in Metroid's original printed manual that described how pirates seized a capsule containing a recently discovered alien lifeform in suspended animation from a deep-space research vessel. The hero is a woman, much like Metroid's Samus Aran, but that fact isn't hidden as it was in Nintendo's original game and instead she jumps and rolls about Rogue Dawn's many 2D platforms with her long locks flowing from the very beginning.
It's a great way to celebrate Metroid's 30th anniversary, particularly since Nintendo didn't really give fans something itself. You can download it and play it on any Nintendo ROM emulator such as Nestopia, but to do so you'll need to download a ROM file of the original Metroid in order for it to work, but Nintendo's lawyers would be really grumpy if we told you how to do that. (For better or for worse, it's not hard.)
In fact, it might not be long before Nintendo's lawyers force the shutdown of Rogue Dawn's website entirely, so hop on this before it's gone (or at least becomes harder to find). Don't think they'll be that harsh? When we wrote about a fan project that entirely recreated the Game Boy's Metroid II: Return of Samus so it looked like it was designed for the Super Nintendo, it was taken down less than a day later.