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Mario Kart Wii introduced many new features to the long-running series including motorbikes and 12 racers on-track at once. While the exploitation of the 'wheelie' mechanic was rife back in the day, generally the Wii version is still looked upon as a memorable entry in the series thanks to its online play, accessible nature and the wide variety of characters and tracks.

Ten years after the game’s original launch, a video has now been uploaded about modders discovering an earlier version of Bowser’s Castle in the game. The mysterious “course.0” file, located within the "Koopa Course" game file, was allegedly placed there by Kosuke Yabuki, who most recently worked as the producer of ARMS on Switch, and is previously known for his work on the Mario Kart series.

The course uncovered is described as a "beta" version of Bowser’s Castle. The modders wrote a script to convert the data within the game file into an actual 3D model – by combing two models together (one for the collision data and one for the visual model). Fake development textures were then applied to the track with a bit of guesswork due to the cryptic nature of the file names. This followed with a series of successful steps, and surprisingly – it the track is actually playable.

This video is actually able to show how the beta version of Bowser’s Castle on Mario Kart Wii looks and plays. The footage of the game starts at the five-minute mark. The track even notably works with CPU characters. Take a look at the clip for the full explanation, and tell us in the comments if you used to play the Wii version of Mario Kart.