The following is a (temporary) list of online multiplayer found on Armor Games. Games are organized alphabetically by categories. Please post any missing or new online multiplayer games on my profile and I will update the list accordingly.

Competitive
Play competitively against one or more players by directly facing other players or the environment.

Player vs. Player
Armor Wars - 1v1
Artillery Live - 2v2
Bad Eggs Online - 3v3
Battle Sector - 1v1 or 2v2
Colony - 1v1 with bots or 2v2
Phage Wars Live - 2-4 players
Shell Shock Live - 1v1, 2v2, or 3v3
Vortex Wars - 2-8 players

Player vs. Enviroment
Exit Path - 2-?
Exit Path 2 - 2-?
Hit The Jackpot 3 - 2+?
Platform Racing 2 - 2-4 players

Cooperative
Play alongside one or more players.

Achievement Unlocked 2 - 4 players
Everybody Edits - 1+ players
The Last Castle - 2-3 players