Here is the full list of all 33 Mission: It's Complicated achievements.
Get an ending between two heroes.
Complete the game with Nightgaunt and Wifi.
Complete 10 missions in a row without injury.
Get more than 3 A+'s during a single playthrough without using "Skip."
Achieve 1 kiss between two heroes.
Get one A+ after completing any mission.
Complete 3 missions in a row without injury.
Get the Possibility Stone.
Complete 1 park date between two heroes.
Complete Nightgaunt's interview.
Complete all 5 interviews.
Complete 1 coffee date between two heroes.
Complete second tutorial mission.
Complete Riptide's interview.
Complete Wifi's interview.
Complete Zael's interview.
Complete Zirconia's interview.
Complete first tutorial mission.
Achieve 1 platonic friendship between two heroes.
Get more than 10 A+'s without using "Skip."
Forget to get the Possibility Stone
Achieve 100% in the Gallery.
Get the Ultimate Ending.
Earned all 10 kisses and platonic friendships between all heroes.
Complete the game with Nightgaunt and Zael.
Complete the game with Nightgaunt and Zirconia.
Complete the game with Nightgaunt and Riptide
Complete the game with Zael and Wifi.
Complete the game with Zael and Zirconia.
Complete the game with Zael and Riptide.
Complete the game with Wifi and Zirconia
Complete the game with Wifi and Riptide
Complete the game with Zirconia and Riptide