Planetary Shield Inhibitor or equivalent perhaps?
seems like there is a planet armor inhibitor...and has super large health even sending 1k fleet attacking it for 1 min could only damage 2% of its health..this is insane man!
i can't kill it in time since the ai home world's planet filled with mark Vsss
FF's need supply to work so you'll have to have captured a planet next door to the AI Homeworld to be able to use them there.
The only Mark V/Core ship you can't tag for reclamation should be Core Bombers which is a known issue.
If you're still trying to kill the AI Homeworld using mark II units I'd suggest backing off for a while & gathering more knowledge so you can unlock mark III (and get mark IV free if you have captured an Advanced Factory).
i can't. The thing is im playing snake type map, and now i've reached the stage where the next planet is ai's home world. Subsequent planets seems to have some ai too..and i've already used up all the knowledges in the previous planets. since i cant pass through ai's home world to the next planet..my mission now is to get rid of its home command centre and win!!

but 15 in game hours into it and i still can't figure out.
i could build mark v equivalent ships though through the space dock but that cost alot..and i also have hive golem and microparasites human ships though. now not too sure how to balance everything up.