Wow ambitious to make a multi player game, unfortunately need others to play...

I was able to test the multiplayer by running multiple instances on my local machine and joining my own session. The pink cubes that show up on the second client when they joined don't show up for the first client who had already scooped up their initial crystals, not sure if those are meant to be instanced or shared.  Does satisfy a first pass at what your stated goal was (to get multiplayer in a game) and the other players movements did seem to stay synced, though clearly for online multiplayer there's some networking that needs to get worked out (try a UPnP setup).

Unfortunately there's not really much game there to play (what do I do after we slurp up the first clump of pink squares?), but I'm happy for you that you've learned how to get multiplayer in a game!

Well, sadly there's no one else :/ into the game, although i deleted the little cubes :)

It's missing sound, and well, squares are not that appealing without juice :)

Hope you'll mix everything out next time !

Feel free to checkout my game if you  have the time, I would love to hear your feedback too !