I would like to emit all my particles in one burst, but with a randomised lifespan, so they die over the course of a few frames, rather than all at once. Is this possible?
Next to “Start LifeTime” there is a tiny downArrow. Click it and select “Random Between Two Constants”. Define your two values (for example: 3 - 4). All particles emitted by the particle system will now die between 3 and 4 seconds.