I haven’t quite figured out the fighting yet even though the Megalops have been giving me loads of practice (and supplies). I’ve tried sparkling them to death, but that doesn’t seem to affect anything that I can see other than the light line on the right. I did notice that the evade reduces the light line. After putzing around with them for a while, I always end up using the salvo to finish them off. The few times that I’ve been bested by ships or such, I just used salvo after salvo to try to finish them, but was not fast enough. I’m not sure how the other parts of my arsenal fit in these other battles.
Flares and Seeking raise the enemy’s Illumination; you do damage by using Salvoes, which become available as the enemy’s Illumination increases. The enemy will also try to raise your Illumination so it can try and attack you; you can Evade to reduce your Illumination to avoid that. You can mouse over the bars beside you/the enemy to see the total Illumination you’ve accumulated. Generally, enemies tend to attack at around 50-100 Illumination. Your own attacks become available at 50 and 100 Illumination as well.
The “Britomart” Flensing-Cannon definitely works - it gives an extra attack, usable at the same Illumination level as a Salvo, that’s powerful against zee-monsters - I was able to take down an Albino Moray and a Lorn-Fluke with it.