First of all co op makes this games a much better experience. There is also a lot less GUILT-like missions. That may be a good or bad thing depending on what you loved on the first game. The parasites are also more diverse this time, in SO there were a lot of mission that looked alike. This time you can also choose 2 characters on almost every mission from the start (Aside from healing touch I do not see much difference). There is some online scoreboard. Story mode is longer than the original game.
All that said, I think that the plot this time is a little weaker (not that I loved SO plot). They reuse some concepts too much (every foreign object you have to extract is some king of glass) and there is no new tools so far.
IMO this game is a 8-9 material. Rent it first and buy if you wish to play with friends or love to redo missions for ranks.
Satan said:
"You are for ever angry, all you care about is intelligence, but I repeat again that I would give away all this superstellar life, all the ranks and honours, simply to be transformed into the soul of a merchant's wife weighing eighteen stone and set candles at God's shrine."
