there are 3 good melee characters - Xian (sharp weapons), hip-hop dude (blunt weapons), and some throwing knives guy....
i got really good at targeting with sharps to take out bigger foes (the brutes have a hard time doing anything w/o arms).
the physics model is really specific and precise (and therefore gory). be warned. but after you de-arm a brute, he will head butt you... haha.
The combat is a little floaty (but better than something like skyrim), and since the targeted melee works as advertised, that part lends some heft/weight to the interactions.
i never played online, but co-op is available w/o a code, iirc. there is some DLC, but i didnt play that either (just came out this year)
i've been tempted to pick this back up on sale - as i had a riot with it (i picked it up on gamefly to have a taste, and ended up playing the whole campaign...(if you got addicted to FO3 questing, this is just as bad)