Very Impressive
[+] Worth the money
[+] Worth the wait
[+] The shooting mechanics is very realistic but lacks recoil in some weapons
[+] Playable zombie teams make L4D not boring if some people arent good playing the survivors
[+] Able to choose whether to play as a human or zombie
[+] Lots of game mode: Single Player, Versus etc.
[+] Good graphics
[+] Storyline makes sense
[+] Vote kick option (good for kicking afk players and clearing a slot up for a friend)
[+] Regular updates
The Bad:
[-] Not available in most game stores (here)
[-] Not alot of players
[-] Bots not much of a help
[-] Most people dont have mic, so may lead to lack of team communication
[-] Unfair games, (eg. 4 human vs 2 zombie)
[-] Lack of weapons
[-] Ammo/weapon points doesnt make sense
[-] Mic-spammin kids
[-] Lags