The secret of beating every map in 10-15 minutes is……?

[AxexAxe]

I think there must be a secret in every map, if you find it you can beat it in 10-15 minutes.
I find one in Alexandria, you can find a way to let yellow defend the blue for you. I finished it in 10 minutes.
In Level 13 you may see yellow attack the green fortress and you claim it, and let green help you taking the blue pyramid . I finish it in 18 minutes.
Haven't find the sure way to beat the game in other map yet, but I think there must be one key secret, if you do it right you can use enemy's army to help you solve the hardest part of the problem.