I had a lot of fun with this game back in the day, I think my copy is still playable on the xbox 360.
I had the most fun when playing the game on the highest difficulty and not getting any weapons upgrades at all, I'd still beat the game in less than a day, these days though I simply don't have that kind of free time anymore though, responsibilities and all that. With these particular conditions it wasn't easy yet it wasn't too hard either, it was just right for me and in the end I'd feel badass. I also recall getting 1st in all those ritual running levels thingy.
Overall, it isn't the greatest game ever (why the Aliens?) but it is at least fun as a fan of Predator.