I don't realy know, but you can crack it down :)
Yes, you can play left 4 dead 2 on steam if you buy from Gamestop.
left 4 dead 2 can be downloaded from Steam
Steam.
It is a Key that will unlock the Left 4 Dead 2 in your steam library
You have to download Steam on your computer, then Left 4 Dead 2 can be bought from that.
Steam's Left 4 Dead and Left 4 Dead 2 engines have eliminated bunny hopping.
Short answer: Yes, of course. Technical answer: The operating system in itself, can play Left 4 Dead 2. But to play Left 4 Dead 2 you need good enough parts to run it. Make sure you meet the system specifications on it's steam page.
On the back of the game manual/CD case, or on your Steam account.
You have to use Steam. Google Steam Tank Rush Server IP and then enter that server.
Some games on Steam do. These games include: Day of Defeat: Source Left 4 Dead 2 Team Fortress 2 Half-Life 2 Portal Half-Life 2: Episode 2 Counter-Strike Source Alien Swarm ( Free on Steam) Half-Life 2:Episode 1 Left 4 Dead Half-Life 2: Deathmatch
Shame on you. £30 Steam Currently £15 on Amazon
Join a steam group that has servers associated with it. After you join the group their servers will appear under the steam group servers in-game.