I may have some conflicts as I am playing Exotic Industries which includes this mod, but I've had a serious issue of the leveling of bosses. I'm at an evolution level I haven't even seen the leviathan toxics and the first boss it threw at me was a level 8 which was a complete base wipe moment.

Granted, perhaps a player at the usual playtime of this mod would have had a ton of projectile damage buffs but I went from comfortably defending to completely unable to scratch the boss with uranium shell tank.

Mainly, it appears the leveling of the boss is based off of the size of the corpse pile and not to do with the evolution level in the game? Or it is based off of evolution and that evolution scaling is vastly out of scope of the difficulty of the typical mob waves you are facing.

I'd highly suggest that boss level be capped by evolution (if it is already, that the balance be examined) and that the boss forming should be announced to give the player a chance to get there as traditional defenses seems utterly useless against them.

I was able to learn more about the mob generation with help from the Exotic dev. It does appear it is tied to evolution. At evolution 0.86 or so I encountered my first boss at level 8. I tested a level 1 boss and it felt roughly appropriate to the difficulty... it'd have smashed my defenses but I could have held it off.

Would it be possible for you to expose the boss scaling settings to startup/map?

local function get_evolut_1_to_10(evolution)
return math.min(10, math.max(math.floor((evolution+0.02)*10),1))
end