Here is the full list of all 22 Pixel Puzzle Makeout League achievements.
Unlocked all special themes
Let the timer run out
Couldn't resist
Remade the world / Set off on your own
Remembered what part she is
Found true love
Became partners with Chess
Went on a sneaking mission with Chess
Solved 200 pixel puzzles
Found the truth with Crossword
Learned about Crossword's past
Saved Sudoku
Explored the digital realm
Tried something new with Sudoku
Completed the Puzzle Maze
Became whole with Piecea
Solved 100 pixel puzzles
Made a costly mistake
Survived an encounter with the Villain
Climbed a mountain with Piecea
Got to know a member of the Puzzle League
Escaped the Villain's clutches