Falci: So... finished the main campaign.
If you bought the original at full price, this one should be a no brainer.
The same if you thought that you could have bought the original at full price.
If you didn't like the first, or didn't find it worthy of 10 bucks, this one won't change your mind.
Though the campaign felt a tad bit shorter in the end, it really is awesome and manages to be a bit more varied than the first game too. I also felt the game was harder than the first too, some bosses are hard as heck and you actually die fairly easy in some parts of the game.
I think the worst missed oportunity was Corina. She didn't deserve just a single level in the campaign, she deserved a mini campaign for herself. I also think that the survival mode should feature up to 4 players, not just 2.
The excessive blood on the other hand was a very good adition, I felt it missing too much from the first game.
They're pretty cool folks, you might get a 3 USD DLC with a story for Corina.