Dark Messiah is pretty much the definition of a bad port. Not only did it suffer a terrible dumbing-down that took out a fair bit of the fun and charm of the original version, it didn't get enhanced too much (there's new multiplayer maps and modes, assuming you can find other players) and generally became a worse experience. The nicest thing GameTap can say is that it's still fun to kick things, and sometimes the glitches came about in a manner (i.e., a threatening boss that is stopped by a mighty doorway) that made GameTap laugh away the heartbreak.
Pros: Some decent battles; unintentionally hilarious; it's fun to kick things.
Cons: Way too buggy/glitchy; streamlined into being dumb rather than accessible; way late for a port.