The Tsukihime universe is one of my favorite places to be in the anime world. In my opinion, it's Type-Moon's greatest achievement. This game is a TBRPG which will be a host to many of the characters from that world. Right now, I only have Shiki Tohno but the system is ready to add more and more characters.
If you've never heard of Tsukihime I suggest you read the manga on mangafox or something. It's really good.
Download: It's sad but it seems InstantPlay or GMArcade is not compatible with GM8.1