I'm about 10% in. I kind of suck at the game since it's hard for me to aim. I passed all of the shooting range challenges with my two unlocked characters, but was only able to get silver medals on a few. Wasn't even close to gold on any but the shotgun.
The cops are pain in the ass! Kill a couple of them and you have Choppers, FED's armed with machine guns etc. on your ass. Your character seems to die really easily as well. 4-5 shots and you're done for. In previous GTA's I've gotten into huge gun fights that lasted pretty much as long as i wanted them to, but here, if i try and fight, the cops surround me in a flash and gun me down. Trying to escape 4 stars in a car is not easy either. Hopefully the characters get a health boost at some point.
Trying to find ways to make money, but not making any yet. A lot of the missions I've done so far i haven't gotten any. All in all though, awesome game. Been playing the last three hours. Had to force myself to stop. I want to make the game last if i can and not finish it in five days.