Don't waste your time! It's pretty easy on legendary with the guide below.I would highly recommend running through the campaign on easy/normal and getting all the skulls unlocked before trying this. Once you have all 15 skulls I ended up turning on all the skulls that made it easier and let me tell you, with the skulls on you don't even need a guide. It's a walk through the park and I never had to restart once.
Skulls to activatePain Train - All player units train 50% faster
Bountiful Harvest - Supplies from supply buidings arrive 25% faster
Emperor - All player powers recharge in half of the time.
Total Annihalation - Spartan special ability slams create and even more powerful explosion upon landing.
Firestarter - Grunts and Marines explode on death inflicting damage on enemy units.
Things That Go Boom - Here units unleash a nuclear explosion on death.
Sugar Cookies - All player units have 50% more hit points.
Shadow - Player core infantry units start cloaked.
**Note** The only skull that is beneficial that I didn't turn on is After Party. It spawns units anytime a firebase is destroyed (never happened) and I just didn't want it messing with my population cap.
Basic StrategyEverything was essentially getting air units and upgrading them to max damage/health. Obviously some missions won't allow that, but with the skulls on you shouldn't have any problems with any combination you choose. When aircraft was not permitted I upgraded marines and just kept pumping them out to max cap and assaulting. It depends on some maps, but have at least two anti-air turrets as defense on your base for the banshees are the primary pests that keep coming periodically just to make sure you're aware that your base should have turrets. Too easy.
Anything I'm missing that makes it even easier for you guys let me know and i'll add it. Cheers!
