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