My set up for Atropos-lvl25 (rank up if it helps!):
Hull: SPEED. Ship Modifier: 2xSHIELD. Bomb Mod: HEAL. Weapon:3xBULLET w/SPLIT+HOMING, and 1xBULLET w/AFFLICTION+HOMING. Other than that, study the map for each phase and look for the safe spots, you can actually beat it w/o getting hit, I think. +1
Sparta "Why God?!" Guide:
(I beat it twice just to make sure. Please vote up.)
Buy 63 Gunmen.
Buy The Quaker gun (not the Quake Box tower).
Spend the extra $2750 on anything EXCEPT reload rate for the quaker, or the quake box tower.
In a nutshell, the quaker replaces the quake box in YellowAfterLife's normal mode guide. Just rapid fire stun them. Empty all your rounds, let it reload once, and then when you have 1/3 ammo, shoot again. Note: Enemies on the ground can't be stunned again, so you should stun them right after they all start walking again. The reload timing is pretty well in sync with their stun duration so to get the timing right, wait until you hear the "clu-click" reload sound and fire again. Don't just spam the button though. Good luck and congrats!