Developer Alientrap has announced their 2D Greek platformer Apotheon now has an Online Multiplayer component on Steam with five maps, and three modes (deathmatch, team deathmatch, elimination).
"While developing Apotheon's combat system we wanted to fight each other to really make sure it had a lot of depth - since we didn't live in the same city we added online support early on. The online game modes were one of our favorite parts of the game throughout development - but we decided to not release it with the main game because we didn't want to distract from the large single player adventure.
We've are now planning to release the online modes as a free standalone game - Apotheon Arena, on Steam in the coming months (though this plan depends on how well the beta goes). We want to release it for free so we can have the largest user base possible - and help promote the main single player game. When we release it and with how much content will depend on how this beta goes. "
You can check out the full post on their Steam page here. I asked if this sort of feature might make its way onto the PS4 version.