My older son seems to have a reasonable array of heroes unlocked for LEGO Batman 2:DC Super Heroes at this point, plus the 5 extra villains from the villain pack and a few other miscellaneous characters. However, we had a small problem with Green Lantern. Around the Gotham Zoo area, there are some piles of green translucent bricks that are made for the Lanterns to build. Holding the circle button (PS3 version) is supposed to build the group of bricks into an object, and then the object does whatever it is supposed to do and leave behind a significant number of LEGO studs. However, we here having the problem that the group of bricks would be built and then no action taken. Once the built bricks lay dormant for a moment, they disassemble, and then we were left to try again. It didn't seem to matter if some of the extra options were turned on or not. The only thing that seemed to resolve the issue was exiting to the main PS3 menu and restarting the game.
I had a different problem previously - after I loaded the villain pack the first afternoon, I started my own game but picked 'Load Game' even though I was pretty sure that there wasn't a game on my profile to load. It appeared to start a new game, but it locked up at the first save point. I played again the next day, and was correctly kicked out of the 'Load Game' screen into the 'New Game' screen the second time and had no problem saving the game.
I don't know if there are more bugs to find, or if this is even the sort of game that will be bothered to be patched. We had problems with the Wii LEGO games locking up periodically, but of course those games didn't get patched.