GBA tech demo
The above video supposedly shows a prototype demo of the unreleased Mario Kart XXL that was created by Denaris Entertainment, a company run by the developer of the Turrican series, Manfred Trenz.
My search for more information has left me mostly empty handed, so all we have to go on is the awful looking prototype above. For all I know this is an elaborate fake, but it seems like a really strange thing to fake; though the title screen of the prototype is a modified version of GameCube’s Mario Kart: Double Dash!! box art. The person posting the video just has videos of prototype games on their channel, so that leads me to believe it may be real.
Either way it looks like hot garbage, so I’d say we didn’t miss out on much.