The predator story is the same as on the XBOX (albeit slightly embellished), which is basically like the PC story, but sort of alternate universe...people look different and who does what is changed quite significantly. The levels are completely different to the PC version. The evolution story is completely new and sees you shooting up pirates, and tribes-people later on.
The game has its moments, but is inferior in every way to the PC version, especially the AI...special mention should go to the way the look-stick (r-stick) feels (worse than PDZ). On live! some of the team-play modes play a lot like TFC, which is nice.
My evolution save corrupted right at the end so I decided to sprint through the game killing the bare minimum of foes (most fun I had with the game!), took my <2hrs to finish this way. Evolution is short.