I’m not sure if this is actually a bug or something else, but it’s a rather strange behavior of the particle emitter. Basically, I wanted the particles to go upwards with the tip pointing downwards, but each time they positioned themselves sideways with the tip pointing to the right. The only solution I found to fix the issue was to rotate the sprite like this in Piskel.
I’ve had a quick play around with it, and no matter which way the emitter is rotated, the particles still come out sideways. This does appear to be a potential bug. Unless one of the GDevelop devs can explain why not.