Hi I gave it a go.
it crashed to a black screen on windows 10 after about 5 minutes of play.
That was probably the "Game Over" screen (after a player loses 3 lives)
I've uploaded a new version which just keeps playing.
The new version also introduces "paradoxes" (hence the name Paradox Event).
Every 30 or so seconds a bullet comes out of a portal without anyone shooting a bullet into the opposite portal, which is a paradox. To solve this players have to work together to shoot one bullet into the opposite portal to restore the timeline. If they don't succeed the timeline is disrupted and weird things will happen. I'm still thinking about what will happen. Maybe the whole game will crash, players start disappearing (like Marty Mcfly) or players just lose some points.
But the whole idea behind this, is that the game switches from player vs. player to a coop game every now and then.