Pretty Good
Brings more variables to the table than the first, but significantly harder than the first. You should still have a relatively low learning curve even though it's a sequel--look at the Half-life episodes, for example; even though the only people who would really play them are those who played Half-life 2, both 2 and 3 start out easy enough so that you can ease back into the gameplay. LS2 is too tough, even for someone who played the first a bunch of times.
Also, it kept glitching on me-- I'd suddenly find myself unable to switch weapons or shoot, and then the zombies would just kill me after knocking down my fort.