Killing Floor (you can't really "drop" it, but I uninstalled it with no intent on re-installing it)
I usually don't really mind if a game has voice acting, but gosh din darn was that games voice acting painful.
Also, the fact that it didn't save me settings every time I booted it up was annoying. Also the fact that it started every mission on "Beginner" difficultly.
As soon as I realized I was on that difficulty, I'd be on wave 7.
There was a few other things I could go into, but to keep it short: I overall don't like this game in the slightest.
There are much better games for 4 player co-op.
cough cough.
Edit - Although I just said that, when I bought it I was given 3 guest passes; meaning anyone I give it to can play the game for free for one month.
So just PM me if your curious about it.