That aside... it's not the first game/toy about illustrating relativistic effects that I've seen before, for instance there's http://lightspeed.sourceforge.net/ and a funny little Flash game that I've tried: http://www.testtubegames.com/velocityraptor.html . Neither of them were very much fun.
This game was not very much fun either, but there was some promise, because at the end once I'd gathered all the orbs by moving slowly and methodically, I enjoyed skating around the level and trying to go as fast as possible without bumping into things. Hopefully someone will use the engine (they say they're releasing it next year) to do something really good.
Looks like the site it was hosted in is gone, though.