In vanilla Factorio, firing an artillery shell will cause a retaliation wave if it hits biters, I haven't experienced the ballistic missile causing the same behaviour. Would it be possible or a good idea to add a similar feature, or the option to toggle one on?

Would be great. I'll see if I can implement it - I have no idea how this works at the moment to be honest.

Would be great. I'll see if I can implement it - I have no idea how this works at the moment to be honest.

Hi, I just tested a retaliation attack by modifying the code directly.
https://gist.github.com/Jvs34/08ca9931e27f6c8cd2a09d9dd881131f

It goes in the "missile-hit" event check, in the same place as spawning the projectiles but just before it.
I took the liberty of adding a config check, would be nice if you added the corresponding setting for it so that it can be toggled off.

The way it works is that it grabs any enemy on the hit location and creates an attack group to send immediately towards the source and they'll attack anything in the way.

The 150 radius in the find enemies call is something I didn't really check to see if it's balanced or not, could be be increased by the explosion radius, up to you.

One thing to note, I have not tested this with stuff like demolishers, pentapods or even pvp.