Best underrated multiplayer game?

Nuclear Dawn!

REALM OF THE MAD GOD!

IMO it must be life.

It's the single biggest MMO out there, with billions of people playing. Photo-realistic graphics, great sound assets, very customizable and smooth controls. However it's not Free 2 Play (I would even argue it's almost Pay 2 Win!), I have a mixed feelings about admins (some are great, others ban without reason), cheating is quite common and it's hard to rise to the top. It also only offers hardcore mode, where you get only one life and if you die it's over, so plenty of players complain about the difficulty. On a more positive note, expansions are usually free, new content is flowing and making the game interesting. Lots of players group to form various guilds (Countries, Nations, Corporations etc, plenty of different ones out there) and you can be member of multiple guilds too! Some don't like it though and complain to the admins, so better check out before you do that. Raid bosses are plentiful, often requiring multiple guilds do bring down. Gear drops every now and than, sets are ingame (Adidas outdoor set, Puma athlete etc...) and mounts are great (machines and animals mostly). Watch out if you love PvP it's heavily regulated and even outlawed in most parts of the ingame world, you don't want to get owned by admin squad, do you? Overall, it's quite entertaining, very accessible even though it's sometimes boring or maybe even frustrating. I recommend this the game all of you, try it and see whether you agree with me or not. VERY underrated game.

Sniper Elite (the first one) has... er... had great multiplayer... until they stopped all online support. its really sad.. Booster Trooper was also a fun multiplayer game, but they stopped online support for that too, I think. Sanctum is a really cool Co-op game, but i think the severs are mostly empty, so unless you have friends to play with, idk if you would like it.

NEOTOKYO°

SimCity, if you can ignore EA crappy servers and syncing, permanent connection, Origin, blah blah... The rest of the game are good for a multiplayer game

Red Orchestra 2. Not nearly enough people playing it, and it's a really good game if you give it time.