Here is the full list of all 22 InfiniPicross achievements.
One Continue
First Solve
3x3 or Bigger Completed
5x5 or Bigger Completed
5 Solved
10 Solved
25 Solved
50 Solved
100 Solved
10x10 or Bigger Completed
15x15 or Bigger Completed
25x25 or Bigger Completed
50x50 or Bigger Completed
99x50 (or 50x99) or Bigger Completed
5 Continues in a Row
10 Continues in a Row
Reset a Filled Grid
Create a Theme
Change Theme
Use The Workshop
Set a Seed
A Certain Familiarity