Use this engine (your choice to credit, as long as you don't claim it's yours) to make a multiplayer game. You can do whatever, it just owns the main purpose of being in the same game on different devices. The max players you can get is currently 2, but you can change this. I hope this works for you.
WARNING: If somebody leaves, it will randomly delete somebody off the players list, which can be confusing to other players who are still ingame and got deleted off the list. I am not sure how to fix this, sorry. Also, it doesn't (for some reason) show both players in the list. ;-; NOTES: Now it is much faster on changing the 'Players' variable when somebody leaves, compared to my other online multiplayer game.