Here is the full list of all 25 Project Myriad achievements.
Defeat 500 Enemies
Defeat 5000 Enemies
Defeat 15000 Enemies
Defeat 10 Star Bosses
Defeat 100 Star Bosses
Defeat 250 Star Bosses
Achieve Wave 30 on 5 Different Levels
Achieve Wave 30 on 15 Different Levels
Achieve Wave 30 on 25 Different Levels
Build 125 Towers
Build 350 Towers
Build 700 Towers
Upgrade 50 Towers to Max Level
Upgrade 100 Towers to Max Level
Upgrade 200 Towers to Max Level
Achieve Wave 40
Achieve Wave 50
Achieve Wave 60
Achieve Wave 70
Achieve Wave 80
Achieve Wave 90
Get to Wave 20 on Hard
Get to Wave 30 on Hard
Get to Wave 40 on Hard
Get to Wave 30 on Extreme