Let's see.
Well to tell the truth I'm a really big fan of this kind of game, I have to say that I really did enjoyed it as much as one could, this one is obviously better than it's predecessor, the upgrade system, varied weapon, fast paced gameplay, excellent save system and the good amount of levels is what makes this game as good as it is,
There were a few enemies that were invincible, but they were harmless as well... But I don't think they were ment to be, I saw like 2 of them in the entire game, just tought I'd point that out.
Great job.