Age of Mythology: Retold

The achievements don't unlock until you exit to the campaign menu. As stated in the other solution, it is possible to cheese the missions by using the "THRILL OF VICTORY" cheat during the campaign. You would only have to play the last mission legit in order for the achievement to unlock.

Mission list for the Fall of the Trident campaign:

--- Greek portion ---
1. Omens (Poseidon)
2. Consequences (Poseidon)
3. Scratching the Surface (Poseidon)
4. A Fine Plan (Zeus)
5. Just Enough Rope (Zeus)
6. I Hope This Works (Zeus)
7. More Bandits (Zeus)
8. Bad News (Zeus)
9. Revelation (Zeus)
10. Strangers (Zeus)

--- Egyptian portion ---
11. The Lost Relic (Isis)
12. Light Sleeper (Ra)
13. Tug of War (Set)
14. Isis, Hear My Plea (Isis)
15. Let's Go (Isis)
16. Good Advice (Zeus, Hades) (second part played with Red color)
17. The Jackal's Stronghold (Isis)
18. A Long Way From Home (Isis)
19. Watch That First Step (Isis)
20. Where They Belong (Ra)

--- Norse portion ---
21. Old Friends (Zeus)
22. North (Thor)
23. The Dwarven Forge (Thor)
24. Not From Around Here (Loki)
25. Welcoming Committee (Loki)
26. Union (Thor)
27. The Well of Urd (Odin)
28. Beneath the Surface (Thor)
29. Unlikely Heroes (Thor)
30. All Is Not Lost (Thor)

--- Final portion ---
31. Welcome Back (Zeus)
32. A Place in My Dreams (Zeus)

If you want to do this quickly you can just open the chat box using enter and type "THRILL OF VICTORY" to win each mission. Just make sure you play the last mission normally (can do it on Story difficulty) in order to unlock the achievement. This is the case for all campaign achievements.