Here is the full list of all 20 Recursion Deluxe achievements.
Completed Sky Temple!
Completed Honey Swamp!
Collected every star in Bumbling Plains!
Completed Bumbling Plains!
Completed Bumbling Plains without dying!
Collected every star in Honey Swamp!
Completed Honey Swamp without dying!
Collected every star in Sky Temple!
Completed Sky Temple without dying!
Completed Ancient Hive!
Collected every star in Ancient Hive!
Completed Ancient Hive without dying!
Built and play-tested a custom level!
Found a hidden statue and conquered its challenge!