I, being a person who plays a lot of pc games understands why the games has to be installed on the ps3 hard drive. The ps3 is a lot of ways like a pc. All pc games is installed on the hard drives to play.
Reasons:
1. Allow the game to load a hell of lot faster when loading new data from the hard drive to the ram, than from the disc.
2. Less wear on the blu ray lasor. No need to get data from game disc. Once the game is install the disc is only needed to verify you have a legit copy of the game to play. Like the pc.
3. Now that the game disc don't have to spin up to send data. That means no blu ray drive noises. The xbox360 dvd drive is always spinning to transfer data to the ram and that's why it's so loud.
Good point, the loading is always faster on the PS3.
I've played the game for 6 hours now...and I only @ mission #3..thats right I am little slow...thats because I am trying to do all the secret missions + getting all the secret orbs..
Overall this game will keep me entertained for the next few weeks.
BTW the online ranking wow, those Japanese dude's occupied the first 100+ rankings..