Dead rising 2 is not rubbish. Its replayability is excellent not only because there are multiple endings to achieve and unlimited number of zombies to kill but also due to the fact that there are mods and trainers out there to spice up the game.
I have recently downloaded a mod which gives you unlimited ammo and forever durability on some weapons. The mod also allows me to carry multiple freedom bears at once. So what I do is I set out 4 freedombear as sentry guns and have 8 followers with machine guns and sniper rifles and do the endless slaughter. Blood everywhere :)
The initial patch takes about 10 minutes max. No trouble for me at all. Oh except for the User control thing that restricted me from installing the game at the beginning. I just needed to disable it during the installation.
Great game. Get it. My favourite weapon is slege hammer. Love the sounds it makes when it comes into contact with zombie flesh :)