Here is the full list of all 18 ZEROCRON achievements.
Explode for the first time.
Reach Level 10 with zero deaths!
Reach Level 20 with zero deaths!
Reach Level 30 with zero deaths!
Reach Level 40 with zero deaths!
Beat level 31 in normal difficulty run
Beat level 31 in HARD difficulty run
Beat level 31 in HYBRIS difficulty run
Beat level 61 in normal difficulty run
Beat level 61 in HARD difficulty run
Beat level 61 in HYBRIS difficulty run
Beat level 91 in normal difficulty run
Beat level 91 in HARD difficulty run
Beat level 91 in HYBRIS difficulty run
Beat ZEROCRON on normal difficulty run
Beat ZEROCRON on HARD difficulty run
Beat ZEROCRON on HYBRIS difficulty run
Beat ZEROCRON on easy difficulty run