Liking the demo as is, it's unfortunate it got canceled. I'd hate to say this but the demo ironically went the same way as what it what it was recreating. When I was playing though, it did feel like I was playing a remastered version of Sonic X-treme if it never got canceled, especially with the Sonic X-treme character mod.
Even if it's not finished, it's great for what it is!