A kart race that never happened
Way back in 2004, development studio Denaris Entertainment Software put together a tech demo for a Mario Kart game on Game Boy Advance called Mario Kart XXL. Their hope was to pitch the concept to Nintendo and get a job working on the next handheld Mario Kart title, following up on the success of Mario Kart: Super Circuit. That never ended up happening, but the demo has recently been discovered and posted by the Nintendo preservation site Forest of Illusion.
The demo features two modes: Demo and Play. In Demo mode, a demonstration plays of Mario riding his kart around a track, showcasing the game’s graphics and camera movements. In Play mode, you can actually control Mario on said track, though there are no items or other racers, and the coins are just for show.
It seems that this demo was adapted from an earlier demo the studio made for a monster truck racing game called “R3D-Demo”. They later went on to produce a Crazy Frog kart racing game, which received less than stellar reception. You can check out a video from channel Hard4Games embedded above, which showcases more of the demo and its history.