For stage one just use the cheap swordmen, they may not kill alot but you get more exp for dieing than killing.

When your on stage two do the same thing use the cheap swordmen.

Stage three is the same thing too only its cheap gunmen.

Now before you level into stage four make sure you have several units on the battlefield because if not while your seeing you is the new antichrist, your enemies are still attacking.

When your in stage four you want to mainly just survive, so use the swordmen mainly, but when the enemy seems to be closing in on you use swordmen, gunmen, gunmen. And that should help.

When your finally in the fifth and final stage juse use whatever units you want until you have around 40,000 saved up. Then rain down your armegeddon and then make vehicle after vehicle until the enemy is destroyed, you may need to use armegeddon several times before you get a clear path.