Here is the full list of all 15 Zack Zero achievements.
Finding all Nahirg treasures.
Finish the game.
Finishing the rock and lava cave level.
Finishing the cave levels.
Reach Zack's suit level 20.
Finishing the outside of the Nahirg’s planet level.
Completing the Nahirg's base levels.
Use rock spikes to kill 50 enemies.
Kill 50 enemies using each of Zack’s powers.
Killing a Nahirg general using only the blade launcher.
Use the power of your rock punch to kill 50 enemies.
Kill 100 enemies using the flame thrower.
Find 5 nahirg treasures.
Use frozen air to freeze 50 enemies.
Killing 100 enemies with the blade launcher.