Here is the full list of all 19 Zengeon achievements.
The base game contains 14 achievements, and there is 1 DLC pack containing 5 achievements.
Use Hou Shu Yan finish the game in single play
Use Yuan Zi Yu finish the game in single play
Use Liu Mu Ying finish the game in single play
Use He Ruo Lin finish the game in single play
Use Mu Rong Yu Qin finish the game in single play