The mod has come a long way since Robert and Alex first began work in January 2011. According to the YouTube description for the Galaxy 2 video, he has been the mod's driving force so far: Chadderz made some astonishing progress on this in the past couple of weeks, successfully splitting the screen, making each character react to a different controller, making the buttons work properly, making one Mario and one Luigi appear in the first place, and most importantly. Alex, on the other hand, thrives on the coding challenge. For him, the allure of modding is that it's a different way to enjoy a game he already loves. Alex is "the main mastermind behind the magic," said Robert, since he "does the majority of the modding and coding." Robert helps out, but he mainly serves as the idea man who takes care of "menial tasks," and also handles the team's video production duties. In this brotherly collaboration, each member has his own areas of expertise. When asked why he and Alex have kept this up for years, Robert said, "We like seeing others using and enjoying our mods, as it makes all the effort put into making them seem extremely worthwhile." It was their first custom track, and as something no one had ever seen before, it remains their most popular video by far, with over 300,000 views since August 2009. So he and Alex, who goes by the moniker Chadderz, examined the game's files, and eventually hacked the Rainbow Road track from Super Mario Kart on the SNES into Mario Kart Wii. "I had played far too much Mario Kart Wii and thought it'd be really nice if more tracks could be added to the game," said Robert. The Chadwick brothers are computer science students in the UK who began modding Wii games in 2008. Robert told Polygon in an email that while it's "difficult to predict" when the mod might be finished, he and Alex "hope to release a playable demo before the end of the year." It's an immediately impressive proof of concept, although it's apparent that there's still a lot of work to be done. But earlier this month, Robert Chadwick, the user MrBean35000vr on YouTube, posted a video (see below) of horizontal split-screen play that he and his younger brother, Alex, hacked into the game. The only multiplayer mode in Galaxy 2 lets a second person play as an orange Luma, a helper character who can attack enemies and collect items. Two brothers are working on a Super Mario Galaxy 2 mod that will bring true split-screen co-op support to the game, and for the pair of longtime modders, it's their most ambitious project yet.