I see it uses Microsoft's XNA, and at least that part will require an alternative, yeah. I'm sure they are indeed on it, as yep, it can be done realistically :). Seeing this tracker on other systems, too, would be great; I'd love this on Linux. As a side note, "C# with Microsoft libraries" doesn't indicate a problem per se these days, as .NET and Microsoft's C# ecosystem is properly open source and cross-platform. No problem developing and running that stuff on Linux nowadays. It's the XNA that's "from the old world", so to speak xD