Finally, you aren't really qualified to judge the open-endedness of Chaos Theory (or Hitman) if you've only played the demo. Finish the whole game and then pass judgment.
If a demo isn't there to judge whether the game is worth my 6-8 hours (as I think that's how long both of those were) then why even have it?
I downloaded the demo. I disliked it. Why would I go any further? Unless you mean pirate it because I didn't think it was good enough for even $5, but the real issue isn't money, it's time. The game wasn't good enough for my handful of hours. As for Hitman 4, I played at least through the level in which you infiltrate a mental institution. I remember going that far. I don't know if I finished it.