Being able to pick chapters, like in MANHUNT 1 & 2 would have been nice....But there is six save spots on the card, if you save each chapter at the start of the chapter, in each of the 6 spots, you would be able to go back to each one.....I have the "Christmas is Here" spot saved where there is no clock, before you go to the office for your "present" -- you can go around the game (except Blue Skies") and do whatever you want (just DON'T go to the office).....
As far as fighting, Endless summer continues even after 100%, you are able to go around the whole game and beat up anybody you want.........