if you add a firework effect and a shape in the same firework (e.g. the bigger ball effect fire charge and the trail effect dimonds) and i also thin there has to be a coloureds dye in them too, i have tryed diffrent combinations of fireworks to see which crash the games and fireworks with only dye dont crash it, fireworks with only effects dont crash it and fireworks with only shapes dont crash it but if there all togethr in one firework it crashs the whole game and its really annoying, i play on xbox one, also i think you have to have mutiple firework stars with both and effect and shape in them in one firework ( e.g. red firework star creeper shaped with a trail, and blue firework star star shaped with a twinkle, in one firework). when it freezes it stays frozen for about 20 seconds then shuts down the entire game, this means i have to reload it and that takes a long time.