You need 100% to unlock Ras al Ghul. Check to make sure you rescued all the hostages. Should be one in each non-vehicle level, it'll show a smiley face if you rescued them and a sad face if you haven't.

As for the last data file, it's nothing interesting, just says "the end". If you want to get it, it's 4 billion studs, so just turn on all your multipliers and you'll get there eventually.