A new release is available with some fixes that were made to the source a while back. The project still lives at SynthesiaGame.com, but these were critical problems that should have been fixed in the open source version.
Synthesia became closed source as of release 0.6.2. The existing source will remain here (and even have periodic bug fixes to the MIDI library as they're found), but the closed project can now be found at http://www.synthesiagame.com/
External MIDI device output now works on Mac. Many Mac bugs fixed. A couple Windows bugs fixed. Overall, this was a bug-fix release. The upcoming 0.6.2 will begin adding many new features.
New Mac version with completely new OpenGL graphics.
MIDI input is now played back in the correct instrument. There are 10 sample songs included from Game Music Themes. There is a new installer and tooltips for all the menu controls. Enjoy!
MIDI input is now supported! A scoring system with combo multiplier has also been added. Enjoy!
(Synthesia) 0.5.0 should be released by the end of the January with MIDI keyboard input support and scoring!
The first release of (Synthesia) is now available. Enjoy.