I recently released my first multiplayer online game. It's called Crusader Party, and it was inspired by the game called Hidden In Plain Sight. Essentially it's a free-for-all of a few human players with a bunch of harmless bots, and everyone looks identical, so you can hide by pretending to be a bot, and sneak up behind people to assassinate them. In Hidden In Plain Sight, the incentive to blow your cover was a secondary victory condition of capturing some towers. In my game, you can only win by being the last one standing so the incentive to blow your cover and start killing people is that whoever gets first blood of the day (there is a 45-second day/night cycle) transforms into a more powerful character at night, who can actually survive a single blow and has greater range and area of effect.
I uploaded it on multiple portals but the most accessible is probably Kongregate, here is the link: Crusader Party
Since it's new there may be not enough players online to begin a match, but you can get around that by opening the link in multiple browser windows or tabs.
The server was written in NodeJS using SocketIO.