In 2007, I played the Crackdown demo more than probably any other Xbox 360 release that year. The demo, not the full game. It was probably a year or two before I bought a copy of the full game, but the Crackdown demo had a generous one-hour timer on it, and in that one hour you could do whatever you wanted. Skill progression was accelerated as well, I think, so in that hour you could easily get to the point where you were jumping over buildings or tossing cars at enemies.
It was amazing. Not only were open-world games relatively new and novel in 2007, but none were as willing to let you break the experience. Nothing was a legitimate threat in Crackdown. And how could it be? You could jump four stories into the air, carry an entire arsenal of explosives, power-lift cars, punch an enemy down an entire city block.
Via:: Crackdown 3 review: Why?