There was a good idea beneath this game.
Let's start by the point that could be improved: if you have th etime, you need to make the goal of the game clear. On Unity, a simple panel on a canvas could perfectly do the trick ! Explain the controls, the goal, etc etc...so that the user isn't lost
In a game jam like that, where you can use every asset, do not forget to put some music and / or SFX. It can seem boresome, but trust me, taking like an hour to put some sounds can REALLY improve a game.
Overall, well job. First, you took a big risk b doing a multiplayer game. Second, you did hand made assets and that's well done. Third, the controls are fun, different powers and all...for a first game jam, you really did great ! Keep up the good work !!