Look at the shadows on the smoke trails, and they're jagged, that's because they're made of lots of small particles in a row, so the shadows are lots of blocks in a row.
imo we need a tag to make particles skip the shadows text, afterall does a brightly burning plasma that fills half the screen really cast a dark shadow underneath it?
There is and you need to redo the textures for the particles.
Textures will either use their alpha channel for transparency or are blended additively. The latter needs a black background and it has to be fully black to the borders, which explains why there are visible borders. The former needs to be fully transparent to the borders likewise, btw.