I have a copy of Messiah, fully boxed, sitting on my computer desk near the computer. Why? No idea, it has just been there for like 10 years.
The game itself is sort of bizarre, was very innovative and yet it fell a little short for not better implementing the core game play mechanics. For one, on harder difficulties, you can only leap into the souls of people who are unaware of your presence, causing you to be stealthy. However, being stealthy was rather difficult and frustrating and it was much better to just play the game on easy so that you could leap into anybody's soul unabated.
another strange flaw was that if you were steadying a weapon, everyone would start to attack you unprovoked, even if there were your supposed allies. The game was full of little things like this that made the game pretty annoying sometimes.