it "sure didn't help matters much". Dave Zdyrko, who operated a prominent Saturn fan site, said: "I don't know if [X-treme] could've saved the Saturn, but ... Sonic helped make the Genesis and it made absolutely no sense why there wasn't a great new Sonic title ready at or near the launch of the [Saturn]". In a 2007 retrospective, producer Wallis said that X-treme would have been able to compete with Nintendo's Super Mario 64. Senn believed that a version of X-treme built by him with Alon's engine could have sold well. Next Generation said that X-treme would have damaged Sega's reputation if it did not compare well to competition such as Super Mario 64 and Crash Bandicoot. Naka was dissatisfied with the game, and in 2012 recalled feeling relief when he learned of its cancellation. Journalists noted similarities in level themes and mechanics between X-treme and the 2013 game Sonic Lost World, although Sonic Team head Iizuka said the resemblance was coincidental. Senn went to work on the Wii U Sonic game Sonic Boom: Rise of Lyric, which was released in 2014 to negative reviews. Prototypes and recreations For years, little content from X-treme was released beyond promotional screenshots. In 2006, a copy of an early test engine was sold at auction for US$2500 to an anonymous collector. An animated GIF image of gameplay was released, and after a fundraising project by the "Assemblergames" website community purchased the disc from the collector, the disk image was leaked on July 17, 2007. Senn created a website with development history including early footage, a playable character named Tiara, and concept music. Senn considered finishing X-treme himself and used some of its concepts in a Sonic fangame, though his plans never materialized. In February 2015, the fansite Sonic Retro obtained the X-treme source code and created a playable build, featuring the level shown in the E3 1996 demo. Reviewing the build, Hardcore Gamer writers described it as rough but inventive, lacking speed but retaining the spirit of Sonic design. They felt it could have been a solid direction for the franchise and a boost for the Saturn had it been completed. A Sonic Retro user began developing a homebrew Saturn game based on X-treme, Sonic Z-treme, in March 2017, and released a build in September 2018. Eurogamer described Z-treme as combining X-treme''-style ideas and levels with new concepts from the developer, and