Here is the full list of all 41 Syndeo-Complex achievements.
Complete stage 01
Complete stage 02
Complete stage 03
Discover all the secrets of stage 01
Discover all the secrets of stage 02
Discover all the secrets of stage 03
Finish stage 01 under a certain time
Finish stage 02 under a certain time
Finish stage 03 under a certain time
Reach the first checkpoint in stage 01
Reach the second checkpoint in stage 01
Reach the first checkpoint in stage 02
Reach the second checkpoint in stage 02
Reach the first checkpoint in stage 03
Reach the second checkpoint in stage 03
Reach the third checkpoint in stage 03
Get the rocket launcher
Kill the sniper
Get the green drug
Reach "Into Syndeo's City"
Reach the control center
Destroy the barrage
Reach zone 04
Reach zone 05
Get the blue drug
Pass the top down view zone
Get the exo
Reach the train
Open the doors of the arsenal
Get the coin
Kill the PROTO-BARON
Kill the OCTO-SKULL
Kill the META-GHOST
Enter in the Inferno
Get the pink drug
Finish the first dome
Finish the second dome
Finish the third dome
Let a SCANA get killed by an ARCHITECTA
Destroy the Prophet 60091 with a lucky rocket and create a paradox
Dropping the PROTO-BARON into the water