I love Left 4 Dead, and I love Left 4 Dead 2 almost as much. A problem with #2 is that they made the hunter useless. The hunter was by far the most fun character to play in #1, but for some reason they decided to make him harder to use and make it almost impossible to do high jumps by closing everything off. The boomer is also worse, but after some getting used to he's ok. But the spitter and charger in #2 are really great and fun to play (the jockey just plain sucks!).
Left 4 Dead 2 has some really hard achievements, and I've been working on them for some time now. The expert maps are almost impossible to do alone and you'll never know who joins a random lobby, so you have to hope that you have some friends who's up for the challange. I managed to force them to do four of the maps (also one on realism), but I still needed Hard Rain. After a lot of waiting and seeing that it probably wouldn't happen, I decided to look for a random lobby. After about an hour a lobby was finally created. Thankfully the players in this lobby turned out to be really decent players, and we actually managed to complete Hard Rain Expert Realism in under two hours, which is just crazy.
I'm really happy to be able to say, 100% complete! Bring on Left 4 Dead 3 =P