Strategies to beat Hardcore mode in First Strike 1.3
When you start the game, DO NOT build a missile or expand the territory. Enemies are not attacking unless you expand the land or build a missile.
Just keep research left-bottom upgrades (icons with an eye) to the 4th, Enhanced Espionage. When you finish this research, enemies' missile silo will be displayed.
Debuild all your weapons. Game will end 'peacefully' when last remaining weapon is debuilded, so you should keep turning the globe to looking for the last one. When the last one is debuilding, just build a missile.
Remaining enemies (maybe 1 or 2) will build some missile, but they didn't make any further actions. So research all techs and devastate whole Earth. :)
(BTW, i'm playing with Android version, so it maybe different on iOS)
EDIT
Just found a better and easier way:
Debuild your weapons right after the game starts.
When you finish debuilding your last weapon, start research.
Enemies will not attack/expand/research. So research all techs and devastate whole Earth. :)