Age of Mythology: Retold

This is an easy achievement.

Start a skirmish with the Greek using Zeus
Settings:

• Standard Mode
• Game Speed Fast
• Infinite resources
• Reveal all
• 1v1s

Start:

1. Begin by building the temple and then upgrade to age 2, select any god.
2. Build an armory and upgrade to age 3, select any god.
3. Build a fortress and upgrade to age 4, select any god.
4. Now in your town hall complete the upgrade called Secret of the Titans.
5. Once the upgrade is complete you will see at the top of your screen to the right side of your god powers is a Titan Gate.
6. Select the Titan Gate and place it down then have your villagers build it, once built you will release the Titan and gain this achievement.

If you need more help with this you can follow my video guide below which will begin at the Wonder achievement and also the Horror Unleashed achievement, as both require the same upgrades to unlock the Titan:

I just now did it in 12 minutes. Start a skirmish with one AI on lowest difficulty. Set ressources to infinite. If you are comfortable with it, increase the games speed.
At the start auto-queue villagers and build a temple, go to the next age. While that is happening, scout towncenters and build houses.
Once you reach the second age, built a forge, advance to the next age, start building additional towncenters. Auto-queue villagers there as well.
Once you got that done, built a fortress, advance to the fourth age.
Once that is done research the Titan Gate technology on a towncenter and gather your villagers at one spot. Once you can, place down the Gate and sent every villager to it. Once it's out, you got the cheevo.
I never got attacked once by the AI in the meantime.